Allowed the boot script to check multiple names for the chez executable.

JOLT_TRACE: map tail-frame history to ns/name (file:line)

.github/workflows/release.yml

@@ -12,6 +12,7 @@ on:
   push:
     tags:
       - 'v*'
+  workflow_dispatch: {}   # dry-run the build matrix without tagging
 
 permissions:
   contents: write   # create/update the GitHub Release and upload assets
@@ -26,10 +27,18 @@ jobs:
         include:
           - os: ubuntu-latest
             target: x86_64-linux
+            shell: bash
           # No x86_64-macos: GitHub is retiring the macos-13 Intel runner (jobs
           # queue forever). Intel Macs build from source. macos-14 is arm64.
           - os: macos-14
             target: aarch64-macos
+            shell: bash
+          - os: windows-latest
+            target: x86_64-windows
+            shell: msys2 {0}
+    defaults:
+      run:
+        shell: ${{ matrix.shell }}
     steps:
       - uses: actions/checkout@v5
         with:
@@ -78,6 +87,65 @@ jobs:
         if: runner.os == 'macOS'
         run: brew install chezscheme lz4
 
+      # --- Windows: MSYS2/MinGW-w64 toolchain + Chez built from source (ta6nt).
+      # The whole job runs in the msys2 shell so cc/xxd/paths behave; the
+      # produced joltc.exe is a plain Windows binary (no MSYS runtime dep). ---
+      - name: Set up MSYS2 (Windows)
+        if: runner.os == 'Windows'
+        uses: msys2/setup-msys2@v2
+        with:
+          msystem: MINGW64
+          update: false
+          # inherit the runner PATH so GITHUB_PATH additions (the chez wrapper
+          # dir) are visible inside the msys2 shell
+          path-type: inherit
+          install: >-
+            git make vim unzip zip
+            mingw-w64-x86_64-gcc
+            mingw-w64-x86_64-lz4
+            mingw-w64-x86_64-zlib
+            mingw-w64-x86_64-ntldd
+
+      - name: Cache Chez Scheme (Windows)
+        if: runner.os == 'Windows'
+        id: cache-chez-win
+        uses: actions/cache@v4
+        with:
+          path: chez-install
+          key: chez-${{ runner.os }}-v10.4.1-mingw64
+
+      - name: Build Chez Scheme from source (Windows)
+        if: runner.os == 'Windows' && steps.cache-chez-win.outputs.cache-hit != 'true'
+        run: |
+          git clone --depth 1 --branch v10.4.1 https://github.com/cisco/ChezScheme.git /tmp/chez-src
+          cd /tmp/chez-src
+          ./configure --threads
+          make -j"$(nproc)"
+          # `make install` drives the unix installsh through cmd and dies; the
+          # build tree has everything — assemble the layout by hand. Boot files
+          # sit next to scheme.exe (that's where the Windows kernel looks).
+          inst="$GITHUB_WORKSPACE/chez-install"
+          mkdir -p "$inst/bin" "$inst/csv"
+          cp ta6nt/bin/ta6nt/*.exe "$inst/bin/"
+          cp ta6nt/bin/ta6nt/*.dll "$inst/bin/" 2>/dev/null || true
+          cp ta6nt/boot/ta6nt/petite.boot ta6nt/boot/ta6nt/scheme.boot "$inst/bin/"
+          cp ta6nt/boot/ta6nt/petite.boot ta6nt/boot/ta6nt/scheme.boot "$inst/csv/"
+          cp ta6nt/boot/ta6nt/scheme.h "$inst/csv/"
+          cp ta6nt/boot/ta6nt/equates.h "$inst/csv/" 2>/dev/null || true
+          cp ta6nt/boot/ta6nt/libkernel.a "$inst/csv/" || { echo "libkernel.a not found:"; find ta6nt -name "*.a" -o -name "kernel*"; exit 1; }
+
+      - name: Put chez on PATH (Windows)
+        if: runner.os == 'Windows'
+        run: |
+          bindir="$GITHUB_WORKSPACE/chez-install/bin"
+          { echo '#!/bin/sh'; echo "exec \"$bindir/scheme.exe\" \"\$@\""; } > "$bindir/chez"
+          chmod +x "$bindir/chez"
+          echo "$bindir" >> "$GITHUB_PATH"
+          echo "JOLT_CHEZ_CSV=$GITHUB_WORKSPACE/chez-install/csv" >> "$GITHUB_ENV"
+          # cc is the build's compiler name; alias it to mingw gcc
+          { echo '#!/bin/sh'; echo 'exec gcc "$@"'; } > "$bindir/cc"
+          chmod +x "$bindir/cc"
+
       - name: Show Chez version
         run: chez --version
 
@@ -86,6 +154,19 @@ jobs:
       # dev-machine check — see jolt-8479). `make joltc-release`, not `make joltc`.
       - name: Build joltc (release)
         run: make joltc-release
+        env:
+          # Bake the release tag into the binary (build-joltc falls back to
+          # `git describe` when this is empty, e.g. a workflow_dispatch dry run).
+          JOLT_VERSION: ${{ startsWith(github.ref, 'refs/tags/') && github.ref_name || '' }}
+
+      - name: Inspect the binary (Windows)
+        if: runner.os == 'Windows'
+        run: |
+          set +e
+          ls -la target/release/
+          ntldd target/release/joltc.exe 2>&1 | head -20
+          ./target/release/joltc.exe -e '(+ 1 2)'
+          echo "exit=$?"
 
       # Sanity: the built binary runs (no Chez needed) and self-reports a value.
       - name: Smoke the binary
@@ -109,21 +190,47 @@ jobs:
           out="$("$work/app/app")"
           test "$out" = "built: 45" || { echo "self-contained build ran '$out', want 'built: 45'"; exit 1; }
 
+      # A built binary must also run the DYNAMIC require path: a namespace not
+      # in the static ns graph compiles from the source roots at runtime, so the
+      # boot's top-level defines must be visible to the runtime compiler's eval
+      # (issue #290: this died with "variable var-deref is not bound").
+      - name: Smoke a runtime require in a built binary
+        run: |
+          joltc="$(pwd)/target/release/joltc"
+          work="$(mktemp -d)"
+          mkdir -p "$work/app/src/app"
+          printf '{:paths ["src"]}\n' > "$work/app/deps.edn"
+          printf '(ns app.extra)\n(defn greet [s] (str "Hello, " s "!"))\n' \
+            > "$work/app/src/app/extra.clj"
+          printf '(ns app.core)\n(defn -main [& _]\n  (println ((requiring-resolve (quote app.extra/greet)) "runtime")))\n' \
+            > "$work/app/src/app/core.clj"
+          ( cd "$work/app" && "$joltc" build -m app.core -o app )
+          out="$(cd "$work/app" && ./app)"
+          test "$out" = "Hello, runtime!" || { echo "runtime require ran '$out', want 'Hello, runtime!'"; exit 1; }
+
       - name: Package
         run: |
           ver="${GITHUB_REF_NAME}"
           name="joltc-${ver}-${{ matrix.target }}"
           mkdir -p "dist/${name}"
-          cp target/release/joltc "dist/${name}/joltc"
           cp README.md LICENSE "dist/${name}/"
-          tar -C dist -czf "dist/${name}.tar.gz" "${name}"
-          ( cd dist && shasum -a 256 "${name}.tar.gz" > "${name}.tar.gz.sha256" )
+          if [ "${{ runner.os }}" = "Windows" ]; then
+            cp target/release/joltc.exe "dist/${name}/joltc.exe"
+            ( cd dist && zip -r "${name}.zip" "${name}" && sha256sum "${name}.zip" > "${name}.zip.sha256" )
+          else
+            cp target/release/joltc "dist/${name}/joltc"
+            tar -C dist -czf "dist/${name}.tar.gz" "${name}"
+            ( cd dist && shasum -a 256 "${name}.tar.gz" > "${name}.tar.gz.sha256" )
+          fi
           ls -la dist
 
       - name: Upload to the GitHub Release
+        if: startsWith(github.ref, 'refs/tags/')
         uses: softprops/action-gh-release@v2
         with:
           files: |
             dist/*.tar.gz
             dist/*.tar.gz.sha256
-          fail_on_unmatched_files: true
+            dist/*.zip
+            dist/*.zip.sha256
+          fail_on_unmatched_files: false

.github/workflows/tests.yml

@@ -56,7 +56,11 @@ jobs:
       - name: Install JDK + Clojure (certify oracle)
         run: |
           sudo apt-get install -y default-jdk rlwrap
-          curl -L -O https://github.com/clojure/brew-install/releases/latest/download/linux-install.sh
+          # --retry + --fail so a transient CDN error retries instead of handing
+          # bash an HTML error page (a 2min timeout page flaked a run)
+          curl --fail --retry 5 --retry-delay 10 --retry-all-errors -L -O \
+            https://github.com/clojure/brew-install/releases/latest/download/linux-install.sh
+          head -1 linux-install.sh | grep -q '^#!' || { echo "installer download corrupt"; cat linux-install.sh | head -5; exit 1; }
           sudo bash linux-install.sh
           clojure --version
 

Makefile

@@ -4,18 +4,23 @@
 # build step. `make test` is the full gate. `make remint` rebuilds the seed after a
 # source change.
 
-.PHONY: test ci values corpus unit smoke buildsmoke staticnativesmoke selfhost sci cts certify ffi transient infer wp devirt fieldread numwp fieldnum protoret narrow directlink numeric inline shakesmoke remint joltc joltc-release joltc-debug joltcsmoke
+.PHONY: test ci values corpus unit smoke buildsmoke staticnativesmoke selfhost sci cts certify ffi transient infer wp devirt fieldread numwp fieldnum protoret narrow directlink numeric inline shakesmoke remint joltc joltc-release joltc-debug joltcsmoke submodules
+
+# Every target needs the vendored submodules; fail with the fix, not a load error.
+submodules:
+	@test -f vendor/irregex/irregex.scm || { \
+	  echo "vendor submodules missing; run: git submodule update --init --recursive"; exit 1; }
 
 # Full gate (dev machine). Includes the self-host byte-fixpoint, which only holds
 # on the same Chez that minted the seed.
-test: selfhost ci
+test: submodules selfhost ci
 	@echo "OK: all gates passed"
 
 # CI gate: behavior only. The checked-in seed is a minted artifact (like a
 # lockfile) — it RUNS correctly on any Chez, but `selfhost` rebuilds it and a
 # different Chez version may emit byte-different (gensym/order) output, so the
 # byte-fixpoint is a dev-machine check, not a CI one (jolt-8479).
-ci: values corpus unit smoke buildsmoke staticnativesmoke sci cts ffi transient infer wp devirt fieldread numwp fieldnum protoret narrow directlink numeric inline certify
+ci: submodules values corpus unit smoke buildsmoke staticnativesmoke sci cts ffi transient infer wp devirt fieldread numwp fieldnum protoret narrow directlink numeric inline certify
 	@echo "OK: CI gates passed"
 
 # Self-host fixpoint: bootstrap.ss rebuild == checked-in seed.

README.md

@@ -9,8 +9,12 @@ runs it on Chez. The compiler is self-hosted: it is written in Clojure
 
 ## Install
 
-Grab the self-contained `joltc` binary (Linux/macOS) — it bundles the runtime,
-compiler, and standard library, so there is nothing else to install.
+Grab the self-contained `joltc` binary (Linux/macOS/Windows) — it bundles the
+runtime, compiler, and standard library, so there is nothing else to install.
+Download the binary archive for your platform from the
+[releases page](https://github.com/jolt-lang/jolt/releases) (`joltc-<ver>-<platform>.tar.gz`,
+or the `.zip` on Windows). The "Source code" archives GitHub attaches to every
+release are not binaries — see [Build](#build) before using one.
 
 With Homebrew:
 
@@ -45,6 +49,18 @@ cd jolt
 bin/joltc -e '(+ 1 2)'        # => 3
 ```
 
+The `--recurse-submodules` matters: jolt vendors its regex engine and test
+suites as git submodules. In a checkout that's missing them (a plain
+`git clone`, or after pulling a commit that adds one), fetch them with:
+
+```bash
+git submodule update --init --recursive
+```
+
+Note that GitHub's auto-generated "Source code (zip/tar.gz)" archives on the
+releases page do **not** contain submodules, so they can't run or build —
+clone the repo instead (or grab a prebuilt binary from the same page).
+
 After changing a compiler source — the reader (`host/chez/reader.ss`), the
 analyzer/IR/backend (`jolt-core/jolt/*.clj`), or the `clojure.core` overlay
 (`jolt-core/clojure/core/*.clj`) — re-mint the seed:

bin/joltc

@@ -14,5 +14,28 @@
 # JOLT_PWD.
 root="$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)"
 export JOLT_PWD="${JOLT_PWD:-$PWD}"
+
+# Identify the Chez Scheme executable
+while read -r CHEZ
+do
+    if [ `which ${CHEZ}` ]
+    then
+	break;
+    fi
+done <<EOF
+chez
+chezscheme
+EOF
+
+# If we failed to find one, whinge and exit.
+if [ ! `which ${CHEZ}` ]
+then
+    echo "No valid Chez Scheme executable found: please install Chez Scheme."
+    exit 1
+fi
+
+# Version for --version / banners: git describe of this checkout, else "dev".
+export JOLT_VERSION="${JOLT_VERSION:-$(git -C "$root" describe --tags --always --dirty 2>/dev/null || echo dev)}"
 cd "$root" || exit 1
-exec chez --script host/chez/cli.ss "$@"
+exec ${CHEZ} --script host/chez/cli.ss "$@"
+

docs/host-interop.md

@@ -258,6 +258,14 @@ transitivity is computed):
 ;; (catch java.io.IOException e …) now matches it; (instance? java.lang.Exception e) is true
 ```
 
+deftype/defrecord classes join the same graph automatically at definition: a
+record's ancestry carries the record interfaces (`clojure.lang.IRecord`,
+`IPersistentMap`, `Associative`, …), a bare deftype carries
+`clojure.lang.IType`, and every protocol the type implements inline appears as
+an implemented interface — so `(ancestors MyRecord)`, `(isa? MyRecord
+clojure.lang.IPersistentMap)`, and hierarchy relationships `derive`d on a
+class's supers all answer like the JVM.
+
 Extending a *built-in* class instead (adding a method to core's `String` shim,
 say) means editing the relevant `host/chez/*.ss` file and running `make remint`
 — see [building-and-deps.md](building-and-deps.md).

docs/spec/02-reader.md

@@ -225,3 +225,31 @@ reader functions are the deliberate exception, S20). Forms read identically
 whether or not they will be evaluated; `read-string` of any printable value
 `v` followed by evaluation yields a value equal to `v` for the
 self-evaluating types (§4 print/read round-trip contract).
+
+## Strict tokens and edn mode
+
+The reader rejects what the reference rejects (corpus `edn / strictness`,
+`reader / strict tokens`):
+
+- A token that starts like a number but doesn't parse as one is
+  NumberFormatException, never a symbol: `1a`, `08` (a leading zero demands
+  octal digits; `042` is 34), `0x2g`, `2r2`. A ratio's parts are plain digit
+  runs (`1/-1` is invalid); a zero denominator is ArithmeticException.
+- Empty ns/name parts are invalid tokens: `:`, `::`, `foo/`, `/foo`, `:/foo`.
+  `/` (division), `ns//` and `:/` (a name of exactly `/`) are valid.
+- Map literals with duplicate keys and set literals with duplicate elements
+  throw IllegalArgumentException at read.
+- An unsupported string escape (`"\q"`) and an octal escape past `\377`
+  (string or `\o` char) throw. A stray close delimiter at top level is
+  "Unmatched delimiter". `\r` terminates a line comment like `\n`.
+- `#inst` validates its calendar fields progressively (month 1–12, day valid
+  for the month including leap years, hour < 24, minute < 60); `#uuid`
+  demands canonical 8-4-4-4-12 hex.
+
+clojure.edn adds on top of that (`__read-form-edn` seam): auto-resolved
+keywords (`::k`) are invalid (no resolution context), each `#_` discarded
+form is validated through the same `:readers`/`:default` pipeline (an
+unreadable tagged element throws even when discarded), `M` literals
+construct BigDecimals, lists satisfy `list?`, and end-of-input honors the
+`:eof` option — an opts map without `:eof` makes EOF an error, while the
+no-opts arity returns nil.

docs/spec/09-core-library.md

@@ -232,6 +232,128 @@ clojure-test-suite `core_test/special_symbol_qmark.cljc` and every
 
 ---
 
+### make-hierarchy, derive, underive, isa?, parents, ancestors, descendants — since 1.0
+
+```
+(make-hierarchy)
+(derive tag parent)            (derive h tag parent)
+(underive tag parent)          (underive h tag parent)
+(isa? child parent)            (isa? h child parent)
+(parents tag)  (ancestors tag)  (descendants tag)   ; + (f h tag) forms
+```
+
+**Semantics**
+
+- S1. A hierarchy is a pure value `{:parents {tag #{...}} :ancestors {...}
+  :descendants {...}}`; the 3-arity forms are pure, the shorter arities read and
+  mutate the global hierarchy.
+- S2. `isa?` is true when `(= child parent)`, when the host type system says
+  parent is assignable from child (both classes), when the relationship was
+  `derive`d — including a relationship derived on one of a class child's
+  supers — or component-wise for equal-length vectors.
+- S3. Class tags answer through the host type hierarchy: `(parents c)` includes
+  the class's direct supers (`bases` — a concrete class's chain roots at
+  `java.lang.Object`, an interface's does not); `(ancestors c)` is the
+  transitive set plus anything `derive`d on the class or its supers. A
+  deftype/defrecord class's ancestry includes its implemented protocol
+  interfaces and, for records, the record interfaces
+  (`clojure.lang.IRecord`/`IPersistentMap`/`Associative`/…; `clojure.lang.IType`
+  for a bare deftype).
+- S4. `derive` returns the updated hierarchy (3-arity) or nil (2-arity);
+  deriving a relationship that already holds transitively, or one that would
+  create a cycle, throws.
+
+**Errors**
+
+- X1. `derive` asserts its argument shapes: parent must be a namespaced Named
+  value; tag must be a class or a Named value (namespaced in the 2-arity
+  global form); `(derive h tag tag)` fails the `not=` assert. AssertionError.
+- X2. `underive`/`derive` with a non-hierarchy `h` throw at the parents
+  lookup (the map is called as a function, like the reference).
+- X3. `(descendants h SomeClass)` throws UnsupportedOperationException
+  ("Can't get descendants of classes") — Java type inheritance is not
+  enumerable downward.
+
+**Conformance**
+
+S1–S4, X1–X3 → corpus `hierarchy / *` rows; clojure-test-suite
+`core_test/{derive,underive,isa_…,parents,ancestors,descendants}.cljc`
+(all fully passing).
+
+---
+
+### atom, add-watch, remove-watch, set-validator!, get-validator — since 1.0
+
+```
+(atom x & {:keys [meta validator]})
+(add-watch iref key f)   (remove-watch iref key)
+(set-validator! iref f)  (get-validator iref)
+```
+
+**Semantics**
+
+- S1. Watches, validators, and reference metadata are one contract (the JVM's
+  ARef/IRef) shared by atoms, vars, and agents. `add-watch`/`remove-watch`
+  return the reference; re-adding a key replaces that watch in place.
+- S2. A watch is called `(f key ref old new)` after a state change: atom
+  swap!/reset!/compare-and-set!, var ROOT changes (`def` on a watched var,
+  `var-set` outside a thread binding, `alter-var-root` — a thread-binding set
+  does not notify), and each agent action's state change.
+- S3. A validator gates every state change and, via the `:validator` ctor
+  option, the initial value — an invalid initial value never constructs the
+  reference.
+- S4. The `:meta` ctor option attaches reference metadata (`meta` reads it,
+  `alter-meta!`/`reset-meta!` update it); nil is allowed.
+
+**Errors**
+
+- X1. A rejected value (validator returns logical false or the ctor option
+  fails on the initial value) throws IllegalStateException "Invalid reference
+  state".
+- X2. A non-map `:meta` ctor option throws ClassCastException.
+
+**Conformance**
+
+S1–S4, X1–X2 → corpus `iref / *` rows; clojure-test-suite
+`core_test/{atom,add-watch,remove-watch}.cljc` (the remaining baselined error
+in the watch namespaces is their STM `ref` section — refs are out of scope,
+`stm-refs` in `coverage.md`).
+
+---
+
+### clojure.string coercion, some-fn, ifn? — since 1.2/1.3
+
+```
+(clojure.string/upper-case s) …    (some-fn p & ps)    (ifn? x)
+```
+
+**Semantics**
+
+- S1. The clojure.string case fns and searches (`upper-case`, `lower-case`,
+  `capitalize`, `starts-with?`, `ends-with?`, `includes?`, `index-of`,
+  `replace`) take any Object `s` through its `toString`, like the reference's
+  `^CharSequence`+`.toString` signatures: `(upper-case :kw)` is `":KW"`,
+  `(capitalize 1)` is `"1"`. nil throws (method call on null); a nil `substr`
+  throws.
+- S2. `some-fn` follows the reference arities: at least one predicate
+  (`(some-fn)` is an arity error) and the returned fn chains with `or`, so a
+  no-match result is the last predicate's own falsy value (`false` stays
+  `false`).
+- S3. `ifn?` covers fns, keywords, symbols, maps, sets, vectors, vars,
+  multimethods, promises (invoking a promise delivers it), and a
+  deftype/defrecord implementing `clojure.lang.IFn`'s `invoke`.
+- S4. A `defmulti`/`defmethod` deferred inside a fn body interns/resolves in
+  the namespace it was WRITTEN in (the macros bake their expansion ns), not
+  whatever namespace is current when it runs.
+
+**Conformance**
+
+S1–S4 → corpus `string / toString coercion`, `core / some-fn`, `core / ifn?`,
+`multimethods / deferred definition`; clojure-test-suite string/some-fn/
+ifn-qmark/boolean-qmark/reduce namespaces (all fully passing).
+
+---
+
 ## Authoring notes
 
 - Source examples from the ClojureDocs export (`clojuredocs-export.edn`,

docs/tools-deps.md

@@ -182,6 +182,30 @@ a root, transitively.
 - Source only; compiled `.class` files in a git dep are ignored.
 - git `:git/sha` must be a full SHA (`git fetch` can't resolve a short one).
 
+## Stack traces
+
+An uncaught error prints the message, the top-level source location, and — when
+frames are available — a `trace:` backtrace. In an AOT `jolt build --direct-link`
+binary the frames map to `ns/name (file:line)`; on the runtime eval path they are
+the surviving fn names. Tail-call optimization erases tail-called frames, so the
+default trace shows only the non-tail spine.
+
+A fuller **tail-frame history** recovers the frames TCO erases: each compiled fn
+records itself on entry into a bounded ring-of-rings buffer, so the trace shows
+TCO-elided frames (including the immediate error site) while a tight tail loop
+stays bounded and its non-tail caller context is preserved.
+
+It is **on by default in REPL-driven development** — a `repl` or nREPL session
+turns it on, so an error in code you evaluate or reload shows a tail-frame trace
+with no setup. Because the recording is baked in at compile time, only code
+compiled while a session is live is traced; reload a namespace to trace code that
+was already loaded (e.g. an app's initial `-M:run` load before its nREPL started).
+
+Elsewhere it is off (a small per-call cost, and never emitted into a `jolt build`
+binary). Override with the environment: `JOLT_TRACE=1` forces it on for a whole
+run — including a plain `-M:run`, so the app's own load is traced — and
+`JOLT_TRACE=0` forces it off, even in a REPL/nREPL session.
+
 ## Conformance
 
 The known-working libraries (see [libraries.md](libraries.md)) and the

host/chez/atoms.ss

@@ -23,21 +23,38 @@
   (fields (mutable val) (mutable watches) (mutable validator) lock)
   (nongenerative jolt-atom-v3))
 
-;; (atom init) / (atom init :validator f :meta m): scan the trailing keyword opts
-;; for :validator (the only one with runtime behaviour; :meta is accepted/ignored).
+;; a rejected reference value is IllegalStateException, like ARef.validate.
+(define (jolt-iref-state-throw)
+  (jolt-throw (jolt-host-throwable "java.lang.IllegalStateException" "Invalid reference state")))
+
+;; (atom init :meta m :validator f) — the ARef ctor contract: the validator runs
+;; against the initial value (an invalid init never constructs), :meta must be a
+;; map (anything else is the JVM's IPersistentMap cast failure).
 (define (jolt-atom-new v . opts)
-  (let loop ((o opts) (validator jolt-nil))
+  (let loop ((o opts) (validator jolt-nil) (m #f))
     (cond
-      ((or (null? o) (null? (cdr o))) (make-jolt-atom v '() validator (make-mutex)))
+      ((or (null? o) (null? (cdr o)))
+       (let ((a (make-jolt-atom v '() validator (make-mutex))))
+         (jolt-atom-validate a v)
+         (when (and m (not (jolt-nil? m)))
+           (unless (jolt-map? m)
+             (jolt-throw (jolt-host-throwable
+                          "java.lang.ClassCastException"
+                          (string-append "class " (jolt-class-name m)
+                                         " cannot be cast to class clojure.lang.IPersistentMap"))))
+           (hashtable-set! meta-table a m))
+         a))
       ((and (keyword-t? (car o)) (string=? (keyword-t-name (car o)) "validator"))
-       (loop (cddr o) (cadr o)))
-      (else (loop (cddr o) validator)))))
+       (loop (cddr o) (cadr o) m))
+      ((and (keyword-t? (car o)) (string=? (keyword-t-name (car o)) "meta"))
+       (loop (cddr o) validator (cadr o)))
+      (else (loop (cddr o) validator m)))))
 
 ;; validate a candidate value: a non-nil validator that returns falsey rejects.
 (define (jolt-atom-validate a v)
   (let ((vf (jolt-atom-validator a)))
     (when (and (not (jolt-nil? vf)) (jolt-not (jolt-invoke vf v)))
-      (error #f "Invalid reference state"))))
+      (jolt-iref-state-throw))))
 
 ;; notify each watch (k ref old new), in insertion order (alist is reverse-built,
 ;; so walk it reversed to match add order).
@@ -106,27 +123,87 @@
     (jolt-atom-notify a old v)
     (jolt-vector old v)))
 
-;; --- watches / validators ---------------------------------------------------
+;; --- watches / validators: the IRef seam --------------------------------------
+;; On the JVM these are the ARef contract shared by atom/var/agent/ref. The atom
+;; keeps its record slots (the hot swap!/reset! path); every OTHER watchable
+;; reference type registers a predicate here and stores its watches/validator in
+;; identity-keyed side tables. A ref type makes itself notify by calling
+;; iref-notify at its mutation points (vars do at root set).
+(define iref-arms '())
+(define (register-iref-arm! pred) (set! iref-arms (cons pred iref-arms)))
+(define (iref? r)
+  (let loop ((as iref-arms))
+    (cond ((null? as) #f) (((car as) r) #t) (else (loop (cdr as))))))
+(define iref-watch-tbl (make-weak-eq-hashtable))
+(define iref-validator-tbl (make-weak-eq-hashtable))
+(define (iref-notify r old new)
+  (for-each (lambda (kv) (jolt-invoke (cdr kv) (car kv) r old new))
+            (reverse (hashtable-ref iref-watch-tbl r '()))))
+(define (iref-validate r v)
+  (let ((vf (hashtable-ref iref-validator-tbl r jolt-nil)))
+    (when (and (not (jolt-nil? vf)) (jolt-not (jolt-invoke vf v)))
+      (jolt-iref-state-throw))))
+
 ;; add-watch interns (key . fn) (replacing any existing key, keeping order);
-;; remove-watch drops it; both return the atom. set-validator! installs a
+;; remove-watch drops it; both return the reference. set-validator! installs a
 ;; validator and validates the CURRENT value immediately (Clojure throws if it's
 ;; already invalid); get-validator reads the slot.
+(define (jolt-watch-add alist key f)
+  (cons (cons key f) (remp (lambda (kv) (jolt=2 (car kv) key)) alist)))
 (define (jolt-add-watch a key f)
-  (jolt-atom-watches-set! a
-    (cons (cons key f)
-          (remp (lambda (kv) (jolt=2 (car kv) key)) (jolt-atom-watches a))))
-  a)
+  (cond
+    ((jolt-atom? a)
+     (jolt-atom-watches-set! a (jolt-watch-add (jolt-atom-watches a) key f))
+     a)
+    ((iref? a)
+     (hashtable-set! iref-watch-tbl a (jolt-watch-add (hashtable-ref iref-watch-tbl a '()) key f))
+     a)
+    (else (error #f "add-watch: not a watchable reference" a))))
 (define (jolt-remove-watch a key)
-  (jolt-atom-watches-set! a
-    (remp (lambda (kv) (jolt=2 (car kv) key)) (jolt-atom-watches a)))
-  a)
+  (cond
+    ((jolt-atom? a)
+     (jolt-atom-watches-set! a
+       (remp (lambda (kv) (jolt=2 (car kv) key)) (jolt-atom-watches a)))
+     a)
+    ((iref? a)
+     (hashtable-set! iref-watch-tbl a
+       (remp (lambda (kv) (jolt=2 (car kv) key)) (hashtable-ref iref-watch-tbl a '())))
+     a)
+    (else (error #f "remove-watch: not a watchable reference" a))))
 (define (jolt-set-validator! a f)
   (let ((vf (if (jolt-nil? f) jolt-nil f)))
-    (when (and (not (jolt-nil? vf)) (jolt-not (jolt-invoke vf (jolt-atom-val a))))
-      (error #f "Invalid reference state"))
-    (jolt-atom-validator-set! a vf)
+    (cond
+      ((jolt-atom? a)
+       (when (and (not (jolt-nil? vf)) (jolt-not (jolt-invoke vf (jolt-atom-val a))))
+         (jolt-iref-state-throw))
+       (jolt-atom-validator-set! a vf))
+      ((iref? a)
+       (when (and (not (jolt-nil? vf)) (jolt-not (jolt-invoke vf (jolt-deref a))))
+         (jolt-iref-state-throw))
+       (hashtable-set! iref-validator-tbl a vf))
+      (else (error #f "set-validator!: not a reference" a)))
     jolt-nil))
-(define (jolt-get-validator a) (jolt-atom-validator a))
+(define (jolt-get-validator a)
+  (cond ((jolt-atom? a) (jolt-atom-validator a))
+        ((iref? a) (hashtable-ref iref-validator-tbl a jolt-nil))
+        (else jolt-nil)))
+
+;; vars are watchable IRefs: a root change (def / var-set on the root /
+;; alter-var-root) validates and notifies like Var.bindRoot. The def-var! wrap
+;; pays two weak-table probes per def and only does IRef work on a watched var.
+(register-iref-arm! var-cell?)
+(define def-var!-pre-iref def-var!)
+(set! def-var!
+  (lambda (ns name v)
+    (let ((c (jolt-var ns name)))
+      (if (or (pair? (hashtable-ref iref-watch-tbl c '()))
+              (not (jolt-nil? (hashtable-ref iref-validator-tbl c jolt-nil))))
+          (let ((old (var-cell-root c)))
+            (iref-validate c v)
+            (let ((r (def-var!-pre-iref ns name v)))
+              (iref-notify c old v)
+              r))
+          (def-var!-pre-iref ns name v)))))
 
 (def-var! "clojure.core" "atom" jolt-atom-new)
 (def-var! "clojure.core" "deref" jolt-deref)

host/chez/build-joltc.ss

@@ -46,6 +46,15 @@
 (unless (or jb-release? (string=? jb-profile "debug"))
   (error 'build-joltc "profile must be \"release\" or \"debug\"" jb-profile))
 
+;; Version baked into the binary's saved heap. Prefer $JOLT_VERSION (CI sets it to
+;; the release tag); else derive it from git in this checkout; else "dev".
+(define jb-version
+  (let ((env (getenv "JOLT_VERSION")))
+    (if (and env (> (string-length env) 0))
+        env
+        (let ((s (bld-sh-capture "git describe --tags --always --dirty 2>/dev/null")))
+          (if (> (string-length s) 0) s "dev")))))
+
 (define jb-build (string-append jb-out ".build"))
 (bld-check-toolchain)
 (bld-system (string-append "mkdir -p '" (path-parent jb-out) "' '" jb-build "'"))
@@ -136,11 +145,10 @@
 (scheme-start
   (lambda args
     (set-source-roots! (list \"jolt-core\" \"stdlib\"))
-    (guard (v (#t (jolt-report-throwable v (current-error-port))
-                  (let ((bt (jolt-backtrace-string v)))
-                    (when bt (display \"  trace:\\n\" (current-error-port))
-                          (display bt (current-error-port))))
-                  (exit 1)))
+    ;; JOLT_TRACE at RUNTIME (the env is unset at heap-build), before any app ns
+    ;; compiles, so a `-M:run` traces the app's own code.
+    (jolt-trace-init-from-env!)
+    (guard (v (#t (jolt-report-throwable v (current-error-port)) (exit 1)))
       (cond
         ((and (= (length args) 2) (string=? (car args) \"-e\"))
          (let ((result (jolt-final-str
@@ -164,6 +172,10 @@
   (jb-emit-runtime-embeds out)
   (put-string out "\n;; === embedded jolt-core + stdlib source ===\n")
   (jb-emit-source-embeds out)
+  ;; Bake the version into the saved heap (runs at heap-build; loader.ss defined
+  ;; jolt-baked-version above, so this set! resolves).
+  (put-string out (string-append "\n;; === baked version ===\n(set! jolt-baked-version "
+                                 (ei-str-lit jb-version) ")\n"))
   (put-string out "\n;; === joltc launcher ===\n")
   (jb-emit-launcher out)
   (close-port out))
@@ -245,6 +257,8 @@
 ;; table so `build` can foreign-entry them to spill the bundled Chez boots. On
 ;; Linux dlsym can't see executable symbols otherwise (macOS exports them anyway).
 (bld-system (string-append
-  "cc -O2 -rdynamic -I'" bld-csv-dir "' -I'" jb-build "' '" jb-main-c "' '"
+  ;; the embedded jolt_* arrays must be foreign-entry-visible at runtime:
+  ;; -rdynamic on ELF; on Windows an exe needs an export table (GetProcAddress).
+  "cc -O2 " (if bld-nt? "-Wl,--export-all-symbols " "-rdynamic ") "-I'" bld-csv-dir "' -I'" jb-build "' '" jb-main-c "' '"
   bld-csv-dir "/libkernel.a' -o '" jb-out "' " (bld-link-libs)))
 (display (string-append "build-joltc: wrote " jb-out "\n"))

host/chez/build-smoke.sh

@@ -94,6 +94,28 @@ for frame in 'app.util/deep-boom' 'app.util/mid-boom' 'app.core/-main'; do
     exit 1
   fi
 done
+# A built binary runs -main with *ns* = user, like clojure.main — so a runtime
+# resolve of an aliased symbol is nil (the alias lives in the entry ns, not user),
+# matching the JVM and interpreted joltc rather than the entry ns's alias table. A
+# separate app: `resolve` defeats tree-shaking, so keep it out of the shake test's
+# app above.
+nsp="$(dirname "$out")/nsparity"
+mkdir -p "$nsp/src/nsp"
+printf '{:paths ["src"]}\n' > "$nsp/deps.edn"
+printf '(ns nsp.lib)\n(defn thing [] 1)\n' > "$nsp/src/nsp/lib.clj"
+printf '(ns nsp.main (:require [nsp.lib :as l]))\n(defn -main [& _]\n  (println "ns:" (str *ns*))\n  (println "resolve:" (pr-str (resolve (quote l/thing))))\n  (println "ns-resolve:" (pr-str (ns-resolve (quote nsp.lib) (quote thing)))))\n' > "$nsp/src/nsp/main.clj"
+nspout="$(dirname "$out")/nsparity-bin"
+if ! JOLT_PWD="$nsp" bin/joltc build -m nsp.main -o "$nspout" >/dev/null 2>&1; then
+  echo "  FAIL: jolt build of the ns-parity app exited non-zero"; exit 1
+fi
+nsp_out="$(cd / && "$nspout" 2>&1)"
+if ! printf '%s' "$nsp_out" | grep -q 'ns: user' \
+   || ! printf '%s' "$nsp_out" | grep -q '^resolve: nil' \
+   || ! printf '%s' "$nsp_out" | grep -q "ns-resolve: #'nsp.lib/thing"; then
+  echo "  FAIL: built binary -main ns parity — want 'ns: user', 'resolve: nil', ns-resolve found"
+  echo "--- got ----"; echo "$nsp_out"
+  exit 1
+fi
 # Tree-shaking (opt-in): same result, and an unreachable def (the `twice` macro,
 # expanded at AOT and never called at runtime) is dropped.
 if ! JOLT_PWD="$app" bin/joltc build -m app.core -o "$out" --tree-shake >/dev/null 2>&1; then
@@ -129,4 +151,20 @@ if [ "$got_dr" != "42" ]; then
   echo "  FAIL: built #code data reader — want 42, got \`$got_dr\`"; exit 1
 fi
 
-echo "build smoke: passed (release + optimized + direct-link + tree-shake + compiler+core shake + data-reader)"
+# A script namespace with no -main (just top-level side effects) must build and
+# run its top-level forms, then exit cleanly — not crash calling a nil -main.
+nomain="$(dirname "$out")/nomain"
+mkdir -p "$nomain/src"
+printf '{:paths ["src"]}\n' > "$nomain/deps.edn"
+printf '(ns script)\n(println "no-main script ran")\n' > "$nomain/src/script.clj"
+nmout="$(dirname "$out")/nomain-bin"
+if ! JOLT_PWD="$nomain" bin/joltc build -m script -o "$nmout" >/dev/null 2>&1; then
+  echo "  FAIL: jolt build of a no-main script exited non-zero"; exit 1
+fi
+got_nm="$(cd / && "$nmout" 2>&1)"; rc_nm=$?
+if [ "$got_nm" != "no-main script ran" ] || [ "$rc_nm" != "0" ]; then
+  echo "  FAIL: no-main script binary — want 'no-main script ran' rc 0, got \`$got_nm\` rc $rc_nm"
+  exit 1
+fi
+
+echo "build smoke: passed (release + optimized + direct-link + tree-shake + compiler+core shake + data-reader + no-main)"

host/chez/build.ss

@@ -23,7 +23,7 @@
 ;; --- shell helpers ----------------------------------------------------------
 ;; Run a command, return its stdout as one trimmed string ("" on no output).
 (define (bld-sh-capture cmd)
-  (let* ((p (process cmd)) (in (car p)))
+  (let* ((p (process (bld-sh-wrap cmd))) (in (car p)))
     (let loop ((acc '()))
       (let ((l (get-line in)))
         (if (eof-object? l)
@@ -37,7 +37,7 @@
             (loop (cons l acc)))))))
 
 (define (bld-system cmd)
-  (let ((rc (system cmd)))
+  (let ((rc (system (bld-sh-wrap cmd))))
     (unless (zero? rc)
       (error 'jolt-build (string-append "command failed (" (number->string rc) "): " cmd)))))
 
@@ -57,6 +57,24 @@
 ;; --- toolchain discovery ----------------------------------------------------
 (define bld-machine (symbol->string (machine-type)))
 (define bld-osx? (bld-contains? bld-machine "osx"))
+(define bld-nt? (bld-contains? bld-machine "nt"))
+
+;; Chez's system/process run through cmd.exe on Windows; every build command
+;; here is written for sh (MSYS2 provides it). On nt, spill the command to a
+;; script and run `sh <file>` — workspace paths carry no spaces, and the
+;; script file sidesteps cmd's quoting entirely. Identity elsewhere.
+(define bld-shell-counter 0)
+(define (bld-sh-wrap cmd)
+  (if bld-nt?
+      (let* ((tmp (or (getenv "TEMP") (getenv "TMP") "."))
+             (f (begin (set! bld-shell-counter (+ bld-shell-counter 1))
+                       (string-append tmp "\\jolt-sh-"
+                                      (number->string bld-shell-counter) ".sh"))))
+        (let ((p (open-output-file f 'replace)))
+          (put-string p cmd)
+          (close-port p))
+        (string-append "sh " f))
+      cmd))
 
 ;; The Chez executable, for the isolated compile pass (see build-binary step 4).
 (define bld-chez
@@ -94,14 +112,21 @@
 
 ;; Link flags. macOS Homebrew layout for the kernel's lz4/zlib/ncurses deps.
 (define (bld-link-libs)
-  (if bld-osx?
-      (let ((lz4 (bld-sh-capture "brew --prefix lz4 2>/dev/null")))
-        (string-append
-          (if (> (string-length lz4) 0) (string-append "-L" lz4 "/lib ") "")
-          "-llz4 -lz -lncurses -framework Foundation -liconv -lm"))
-      ;; Linux: the Chez kernel pulls in compression (lz4/z), the expression
-      ;; editor (ncurses + terminfo), threads, dlopen, libuuid, and clock_gettime.
-      "-llz4 -lz -lncurses -ltinfo -ldl -lm -lpthread -luuid -lrt"))
+  (cond
+    (bld-osx?
+     (let ((lz4 (bld-sh-capture "brew --prefix lz4 2>/dev/null")))
+       (string-append
+         (if (> (string-length lz4) 0) (string-append "-L" lz4 "/lib ") "")
+         "-llz4 -lz -lncurses -framework Foundation -liconv -lm")))
+    ;; Windows (ta6nt, MinGW-w64 under MSYS2): the Chez kernel pulls in
+    ;; compression, winsock, COM/UUID, and the registry.
+    (bld-nt?
+          ;; -static: a single-file exe (no libwinpthread/libgcc/lz4 DLL deps) —
+     ;; required for a distributable binary and for TLS init consistency.
+     "-static -llz4 -lz -lws2_32 -lrpcrt4 -lole32 -luuid -ladvapi32 -luser32 -lshell32 -lm")
+    ;; Linux: the Chez kernel pulls in compression (lz4/z), the expression
+    ;; editor (ncurses + terminfo), threads, dlopen, libuuid, and clock_gettime.
+    (else "-llz4 -lz -lncurses -ltinfo -ldl -lm -lpthread -luuid -lrt")))
 
 ;; --- runtime manifest (mirrors host/chez/cli.ss's load order) ---------------
 ;; A line is either literal Scheme text to inline, or a tag whose emission the build
@@ -411,7 +436,15 @@
 ;; direct-link?: opt-in closed-world direct-linking (app->app calls bind directly,
 ;; no runtime redefinition). Off by default in every mode — release stays
 ;; dynamically linked.
+(define (bld-suffix? s suf)
+  (let ((n (string-length s)) (m (string-length suf)))
+    (and (>= n m) (string=? (substring s (- n m) n) suf))))
 (define (build-binary entry-ns out-path mode natives embed-dirs ext-roots direct-link? tree-shake?)
+  ;; Windows executables carry .exe; normalize here so the append-payload and
+  ;; cc paths agree and the shell can run the result.
+  (let ((out-path (if (and bld-nt? (not (bld-suffix? out-path ".exe")))
+                      (string-append out-path ".exe")
+                      out-path)))
   ;; The self-contained path (jolt-embedded-bytes "stub/launcher") needs no csv
   ;; kernel files, no Chez, no cc — only the legacy cc path does.
   (unless (jolt-embedded-bytes "stub/launcher") (bld-check-toolchain))
@@ -538,11 +571,23 @@
                             "))\n"
                             "                (list \"jolt-core\" \"stdlib\"))))\n"))
           (put-string out (string-append
-                            "    (let ((mainv (var-deref " (ei-str-lit entry-ns) " \"-main\")))\n"
+                            ;; Call -main only if the entry namespace defines one;
+                            ;; a script ns (top-level side effects, no -main) has
+                            ;; already run its forms at heap build, so invoking a nil
+                            ;; -main would crash ("nil cannot be cast to IFn") — just
+                            ;; exit cleanly instead.
+                            "    (let ((maincell (var-cell-lookup " (ei-str-lit entry-ns) " \"-main\")))\n"
                             ;; render an uncaught throw (+ Clojure backtrace) instead
                             ;; of Chez's opaque dump, then exit non-zero.
                             "      (guard (v (#t (jolt-report-throwable v (current-error-port)) (exit 1)))\n"
-                            "        (apply jolt-invoke mainv args)))\n"
+                            ;; Loading the app left the current ns at the entry ns; reset
+                            ;; it to `user` before -main, matching clojure.main (*ns* is
+                            ;; `user` when a `-m` -main runs, so a runtime resolve of an
+                            ;; aliased symbol behaves the same as on the JVM / interpreted
+                            ;; joltc, not off the entry ns's alias table).
+                            "        (set-chez-ns! \"user\")\n"
+                            "        (when (and maincell (var-cell-defined? maincell))\n"
+                            "          (apply jolt-invoke (var-cell-root maincell) args))))\n"
                             "    (exit 0)))\n"))
           (close-port out))
         ;; 4. compile -> boot -> link. Two paths, chosen by whether this process
@@ -558,24 +603,70 @@
             (build-self-contained entry-ns out-path mode builddir flat-ss flat-so boot
                                   (bld-native-link-flags natives))
             (build-with-cc entry-ns out-path mode builddir flat-ss flat-so boot boot-h main-c
-                           (bld-native-link-flags natives))))))))
+                           (bld-native-link-flags natives)))))))))
 
 ;; --- self-contained link (in-process compile + append the boot to the stub) ---
-;; compile-file runs with a FRESH scheme-environment as the interaction
-;; environment: the loaded jolt runtime redefines `error` (regex.ss), and flat.ss
-;; inlines that same runtime, so an early reference to `error` (before its define
-;; runs) must bind to the kernel primitive — a clean env gives exactly that, the
-;; same as the legacy path compiling in a fresh Chez process. Without it the boot
-;; dies at startup with "variable error is not bound".
+;; compile-file runs against the DEFAULT interaction environment, so the boot's
+;; top-level defines land in the real symbol cells — the runtime compiler's
+;; eval'd code must resolve them (var-deref, jolt-invoke, the jolt-n* macros)
+;; when the built binary dynamically requires a namespace. Compiling in a clean
+;; copy-environment instead orphans every define in locations eval can't see,
+;; and the binary dies with "variable var-deref is not bound" the moment a
+;; runtime require compiles source.
+;;
+;; The default env has a wrinkle the legacy fresh-Chez path doesn't: THIS
+;; process's cells hold jolt's redefinitions of some kernel names (`error`,
+;; regex.ss), so references to them compile as cell reads — and a read that
+;; runs before the redefining form would find the fresh binary's cell unbound.
+;; The prologue closes that: it first binds each redefined kernel name's cell
+;; to its kernel value, making the boot's earliest reads identical to the
+;; legacy path's primitive references.
+
+;; every top-level (define nm …)/(define (nm …) …) name in the flat file that
+;; shadows a scheme-environment VARIABLE (syntax names don't eval; skip them).
+(define (bld-kernel-prologue flat-ss)
+  (let ((seen (make-eq-hashtable))
+        (kenv (scheme-environment))
+        (names '()))
+    (let ((ip (open-input-file flat-ss)))
+      (let loop ()
+        (let ((f (read ip)))
+          (unless (eof-object? f)
+            (when (and (pair? f) (eq? (car f) 'define) (pair? (cdr f)))
+              (let* ((h (cadr f))
+                     (nm (if (pair? h) (car h) h)))
+                (when (and (symbol? nm)
+                           (not (hashtable-ref seen nm #f))
+                           (guard (e (#t #f)) (begin (eval nm kenv) #t)))
+                  (hashtable-set! seen nm #t)
+                  (set! names (cons nm names)))))
+            (loop))))
+      (close-port ip))
+    (apply string-append
+           (map (lambda (nm)
+                  (let ((s (symbol->string nm)))
+                    (string-append "(define " s " (eval '" s " (scheme-environment)))\n")))
+                (reverse names)))))
+
+;; prepend the prologue to the flat file in place.
+(define (bld-prepend-prologue! flat-ss)
+  (let ((prologue (bld-kernel-prologue flat-ss))
+        (body (read-file-string flat-ss)))
+    (let ((out (open-output-file flat-ss 'replace)))
+      (put-string out ";; kernel-name cells pre-bound so early reads match the kernel primitives\n")
+      (put-string out prologue)
+      (put-string out body)
+      (close-port out))))
+
 (define (build-self-contained entry-ns out-path mode builddir flat-ss flat-so boot native-link)
   (let ((petite (string-append builddir "/petite.boot"))
         (scheme (string-append builddir "/scheme.boot")))
     (jolt-spill-embedded! "csv/petite.boot" petite)
     (jolt-spill-embedded! "csv/scheme.boot" scheme)
     (display (string-append "jolt build: compiling " entry-ns " (" mode " mode, self-contained)\n"))
-    (parameterize ((interaction-environment (copy-environment (scheme-environment))))
-      (compile-file flat-ss flat-so)
-      (make-boot-file boot '() petite scheme flat-so))
+    (bld-prepend-prologue! flat-ss)
+    (compile-file flat-ss flat-so)
+    (make-boot-file boot '() petite scheme flat-so)
     ;; The stub is the native launcher the boot is appended to. With no :static
     ;; natives it's the prebuilt one bundled in joltc (no cc needed); with :static
     ;; natives it's re-linked here from the bundled kernel + launcher source so the

host/chez/cli.ss

@@ -11,6 +11,26 @@
 
 (define cli-args (cdr (command-line)))   ; drop the script name
 
+;; Fail early and actionably when the vendored submodules aren't checked out —
+;; a plain `git clone` or GitHub's auto-generated "Source code" release archive
+;; lacks them, and the raw failure ("load failed for vendor/irregex/irregex.scm")
+;; doesn't say how to fix it. (The self-contained joltc binary embeds these and
+;; never runs this file.)
+(unless (file-exists? "vendor/irregex/irregex.scm")
+  (display "jolt: vendor submodules are missing (vendor/irregex).
+" (current-error-port))
+  (display "GitHub's 'Source code' release archives don't include submodules.
+" (current-error-port))
+  (display "Clone the repo instead:
+" (current-error-port))
+  (display "  git clone --recurse-submodules https://github.com/jolt-lang/jolt.git
+" (current-error-port))
+  (display "or, in an existing checkout:
+" (current-error-port))
+  (display "  git submodule update --init --recursive
+" (current-error-port))
+  (exit 1))
+
 (load "host/chez/rt.ss")
 (set-chez-ns! "clojure.core")
 (load "host/chez/seed/prelude.ss")
@@ -46,6 +66,9 @@
       (when bt (display "  trace:\n" port) (display bt port)))
     (exit 1)))
 
+;; JOLT_TRACE opt-in, at runtime (before any app ns compiles) so the app is traced.
+(jolt-trace-init-from-env!)
+
 (guard (v (#t (jolt-report-uncaught v)))
   (cond
     ;; -e EXPR — evaluate one expression and print it (blank for nil). Wrapped in

host/chez/collections.ss

@@ -298,8 +298,21 @@
 (define empty-pmap-hash (make-pmap empty-hnode 0 #f))      ; hash-order backing (sets)
 (define pmap-absent (list 'absent))    ; unique missing-key sentinel
 ;; PersistentArrayMap threshold: assoc of a new key promotes to hash mode once the
-;; map already holds 8 entries (array.length >= 16 in the reference).
+;; map already holds 8 entries (array.length >= 16 in the reference). Clojure 1.13
+;; raised the limit to 64 for maps whose keys are ALL keywords (the common
+;; keyword-map case); mixed-key maps still cap at 8.
 (define array-map-limit 8)
+(define array-map-limit-kw 64)
+(define (all-keywords? ks)
+  (or (null? ks) (and (keyword? (car ks)) (all-keywords? (cdr ks)))))
+;; Should a map of `cnt` entries with insertion order `ord` stay in array mode
+;; when key `k` is added? Under 8 always; a keyword-only map (existing keys + the
+;; new key all keywords) grows to 64; otherwise it caps at 8.
+(define (pmap-array-keep? cnt ord k)
+  (cond ((fx<? cnt array-map-limit) #t)
+        ((fx>=? cnt array-map-limit-kw) #f)
+        ((and (keyword? k) (all-keywords? ord)) #t)
+        (else #f)))
 (define (append-key ord k) (append ord (list k)))
 (define (remove-key ord k) (let loop ((o ord)) (cond ((null? o) '()) ((jolt= (car o) k) (cdr o)) (else (cons (car o) (loop (cdr o)))))))
 
@@ -310,7 +323,7 @@
   (let* ((added (box #f)) (r (node-assoc (pmap-root m) 0 (key-hash k) k v added))
          (cnt (pmap-cnt m)) (ord (pmap-order m)))
     (if (unbox added)
-        (if (and ord (fx<? cnt array-map-limit))
+        (if (and ord (pmap-array-keep? cnt ord k))
             (make-pmap r (fx+ cnt 1) (append-key ord k))
             (make-pmap r (fx+ cnt 1) #f))
         (make-pmap r cnt ord))))
@@ -352,10 +365,14 @@
         (let loop ((ks ord) (a acc))
           (if (null? ks) a (loop (cdr ks) (proc (car ks) (pmap-get m (car ks) jolt-nil) a))))
         (node-fold (pmap-root m) proc acc))))
-;; map LITERAL ({...}): array map up to 8 entries, hash map beyond (RT.map).
+;; map LITERAL ({...}): array map up to 8 entries (64 if keyword-only, per 1.13),
+;; hash map beyond (RT.map).
 (define (jolt-hash-map . kvs)
   (let loop ((m empty-pmap) (kvs kvs))
-    (cond ((null? kvs) (if (fx>? (pmap-cnt m) array-map-limit) (pmap->hash m) m))
+    (cond ((null? kvs)
+           (let ((cnt (pmap-cnt m)) (ord (pmap-order m)))
+             (if (fx>? cnt (if (all-keywords? ord) array-map-limit-kw array-map-limit))
+                 (pmap->hash m) m)))
           ((null? (cdr kvs)) (error 'hash-map "odd number of map literal entries"))
           (else (loop (pmap-put-ordered m (car kvs) (cadr kvs)) (cddr kvs))))))
 ;; array-map ctor: insertion-ordered regardless of size (createAsIfByAssoc).
@@ -404,9 +421,11 @@
   (if (null? args)
       (jolt-vector)
       (let ((coll (car args)) (xs (cdr args)))
-        (if (jolt-nil? coll)
-            (fold-left jolt-conj1 jolt-empty-list xs)
-            (meta-carry coll (fold-left jolt-conj1 coll xs))))))
+        (cond
+          ;; 1-arity returns the coll untouched — (conj nil) is nil
+          ((null? xs) coll)
+          ((jolt-nil? coll) (fold-left jolt-conj1 jolt-empty-list xs))
+          (else (meta-carry coll (fold-left jolt-conj1 coll xs)))))))
 
 ;; A host shim registers a type's get via register-get-arm! (handler: (coll k d) ->
 ;; value) instead of set!-wrapping jolt-get — disjoint coll types, checked before the
@@ -443,11 +462,16 @@
 (define (rec-coll-method coll name)
   (and (jrec? coll) (find-method-any-protocol (jrec-tag coll) name)))
 
+(define (jolt-nth-nil-idx! i)
+  (when (jolt-nil? i)
+    (jolt-throw (jolt-host-throwable "java.lang.NullPointerException" "nth index"))))
 (define jolt-nth
   (case-lambda
     ((coll i)
+     (jolt-nth-nil-idx! i)
      (let ((i (->idx i)))
-       (cond ((pvec? coll) (let ((v (pvec-v coll)))
+       (cond ((jolt-nil? coll) jolt-nil)          ; RT.nth(nil, i) is nil at any index
+             ((pvec? coll) (let ((v (pvec-v coll)))
                              (if (and (fx>=? i 0) (fx<? i (vector-length v))) (vector-ref v i)
                                  (jolt-throw (jolt-host-throwable "java.lang.IndexOutOfBoundsException" "index out of bounds")))))
              ((string? coll) (if (and (fx>=? i 0) (fx<? i (string-length coll))) (string-ref coll i)
@@ -456,8 +480,10 @@
              ((rec-coll-method coll "nth") => (lambda (m) (jolt-invoke m coll i)))
              (else (error 'nth "unsupported collection")))))
     ((coll i d)
+     (jolt-nth-nil-idx! i)
      (let ((i (->idx i)))
-       (cond ((pvec? coll) (pvec-nth-d coll i d))
+       (cond ((jolt-nil? coll) d)                 ; RT.nth(nil, i, notFound) is notFound
+             ((pvec? coll) (pvec-nth-d coll i d))
              ((string? coll) (if (and (fx>=? i 0) (fx<? i (string-length coll))) (string-ref coll i) d))
              ((or (cseq? coll) (empty-list-t? coll)) (seq-nth coll i #t d))
              ((rec-coll-method coll "nth") => (lambda (m) (jolt-invoke m coll i d)))
@@ -502,6 +528,21 @@
         ((pset? coll) (pset-contains? coll k))
         ((pvec? coll) (let ((k (->idx k))) (and (fixnum? k) (fx>=? k 0) (fx<? k (pvec-count coll)))))
         ((jolt-nil? coll) #f)
+        ;; a string supports contains? by INDEX only (RT.contains: CharSequence +
+        ;; Number key); any other key — or any unsupported type — is the JVM's
+        ;; IllegalArgumentException.
+        ((string? coll)
+         (if (and (number? k) (exact? k) (integer? k))
+             (and (>= k 0) (< k (string-length coll)))
+             (jolt-throw (jolt-host-throwable
+                          "java.lang.IllegalArgumentException"
+                          "contains? not supported on type: java.lang.String"))))
+        ((or (cseq? coll) (empty-list-t? coll) (number? coll) (boolean? coll)
+             (keyword? coll) (jolt-symbol? coll) (char? coll))
+         (jolt-throw (jolt-host-throwable
+                      "java.lang.IllegalArgumentException"
+                      (string-append "contains? not supported on type: "
+                                     (guard (e (#t "?")) (jolt-class-name coll))))))
         (else #f)))
 
 (define (jolt-empty? coll)
@@ -514,15 +555,25 @@
         ((cseq? coll) #f)                            ; a cseq is non-empty by construction
         (else (error 'empty? "unsupported collection"))))
 
+(define (jolt-stack-throw coll)
+  (jolt-throw (jolt-host-throwable
+               "java.lang.ClassCastException"
+               (string-append "class " (guard (e (#t "?")) (jolt-class-name coll))
+                              " cannot be cast to class clojure.lang.IPersistentStack"))))
 (define (jolt-peek coll)
   (cond ((pvec? coll) (pvec-peek coll))
-        ((or (cseq? coll) (empty-list-t? coll)) (jolt-first coll))   ; list peek = first
-        ((jolt-nil? coll) jolt-nil) (else (error 'peek "unsupported collection"))))
+        ;; list peek = first; a non-list seq (range, a rest chain) is not an
+        ;; IPersistentStack on the JVM
+        ((and (cseq? coll) (cseq-list? coll)) (jolt-first coll))
+        ((empty-list-t? coll) (jolt-first coll))
+        ((jolt-nil? coll) jolt-nil)
+        (else (jolt-stack-throw coll))))
 (define (jolt-pop coll)
-  (cond ((pvec? coll) (meta-carry coll (pvec-pop coll)))
-        ((cseq? coll) (meta-carry coll (jolt-rest coll)))            ; list pop = rest
+  (cond ((jolt-nil? coll) jolt-nil)                                 ; RT.pop(nil) is nil
+        ((pvec? coll) (meta-carry coll (pvec-pop coll)))
+        ((and (cseq? coll) (cseq-list? coll)) (meta-carry coll (jolt-rest coll)))
         ((empty-list-t? coll) (error 'pop "can't pop empty list"))
-        (else (error 'pop "unsupported collection"))))
+        (else (jolt-stack-throw coll))))
 
 ;; ============================================================================
 ;; equality / hash hooks called from values.ss (jolt=2 / jolt-hash)

host/chez/compile-eval.ss

@@ -110,6 +110,38 @@
 ;; older seed during the first re-mint pass.
 (let ((scv (var-deref "jolt.backend-scheme" "set-var-cache!")))
   (when (procedure? scv) (scv #t)))
+;; JOLT_TRACE is a falsey value (case-insensitive) — the single predicate both the
+;; dev-mode enable and the whole-run enable consult, so "off" never accidentally
+;; means "on". An empty / unset value is NOT falsey here — it carries no signal, so
+;; dev mode still traces and a whole run still doesn't.
+(define (jolt-trace-env-off? e)
+  (and (string? e)
+       (let ((s (string-downcase e)))
+         (or (string=? s "0") (string=? s "false") (string=? s "no")
+             (string=? s "off") (string=? s "n")))))
+;; Tail-frame history. Turning it on makes the emitter add a per-fn history push to
+;; every fn compiled AFTERWARD, and allocates this thread's ring. Suppressed when
+;; JOLT_TRACE is a falsey value, so JOLT_TRACE=0 / off / no disables it in dev mode.
+(define (jolt-enable-trace!)
+  (unless (jolt-trace-env-off? (getenv "JOLT_TRACE"))
+    (let ((stf (var-deref "jolt.backend-scheme" "set-trace-frames!")))
+      (when (procedure? stf) (stf #t)))
+    (jolt-trace-enable!)))
+;; Exposed so the REPL / nREPL entrypoints (jolt.main, jolt.nrepl) can turn tracing
+;; on for REPL-driven development without the user setting JOLT_TRACE. Because the
+;; push is baked in at compile time, only code compiled after this call is traced —
+;; which is exactly the code you eval / reload in a live session.
+(def-var! "jolt.host" "enable-trace!" jolt-enable-trace!)
+;; Explicit opt-in for a whole run (JOLT_TRACE=1): turn tracing on BEFORE any app
+;; namespace is compiled, so a plain `-M:run` traces the app's own code too. Called
+;; from the runtime entrypoints (cli.ss, and the built joltc launcher) — NOT at load
+;; time: a built joltc runs top-level forms at heap-build time, where JOLT_TRACE is
+;; always unset, so a load-time check would never see the user's runtime env. Only an
+;; affirmative value (set, non-empty, not falsey) forces it on.
+(define (jolt-trace-init-from-env!)
+  (let ((e (getenv "JOLT_TRACE")))
+    (when (and e (fx>? (string-length e) 0) (not (jolt-trace-env-off? e)))
+      (jolt-enable-trace!))))
 
 ;; (with-meta sym m) -> sym, else x — an (ns ^:no-doc name …) yields the name with
 ;; reader metadata as a with-meta form; strip it to read the bare ns symbol.
@@ -211,7 +243,13 @@
 ;; A top-level (do ...) is UNROLLED — each subform compiled+eval'd in turn, like
 ;; Clojure's top-level do — so a runtime defmacro/def in an earlier subform is
 ;; visible (macro flag set, var interned) before a later subform is analyzed.
+;; a non-form VALUE (a function object, a BigDecimal, a reference type)
+;; self-evaluates, like eval on the JVM.
 (define (jolt-compile-eval-form form ns)
+  (if (or (procedure? form) (jbigdec? form) (jolt-atom? form) (jolt-multifn? form))
+      form
+      (jolt-compile-eval-form* form ns)))
+(define (jolt-compile-eval-form* form ns)
   (cond
     ;; thread the current ns: an earlier subform may switch it (ns/in-ns call
     ;; set-chez-ns!), and the next subform must be ANALYZED in that ns so its defs
@@ -229,6 +267,9 @@
      ;; record this form's source location first, so a compile- or run-time error
      ;; in it reports the right place.
      (jolt-enter-form! form)
+     ;; drop tail-frame history from earlier top-level forms, so an error's trace
+     ;; shows only this form's own call history (a no-op unless JOLT_TRACE is on).
+     (jolt-trace-reset!)
      (eval (read (open-input-string (jolt-analyze-emit-form form ns)))
            (interaction-environment)))))
 

host/chez/converters.ss

@@ -117,20 +117,21 @@
      (let ((a (car args)))
        (cond
          ((jolt-symbol? a) a)
-         ;; (symbol "ns/name") splits the namespace at the LAST "/" (JVM
-         ;; Symbol.intern), so (namespace (symbol "foo/bar")) => "foo". A lone "/"
-         ;; or a leading slash has no namespace. The no-ns sentinel is #f — matches
-         ;; emit's quoted-symbol lowering (jolt-symbol #f "x"), so (= 'x (symbol
-         ;; "x")) holds (jolt= compares ns with strict equal?).
+         ;; (symbol "ns/name") splits the namespace at the FIRST "/" (JVM
+         ;; Symbol.intern), so (namespace (symbol "foo/bar/baz")) => "foo" with
+         ;; name "bar/baz". A lone "/" or a leading slash has no namespace. The
+         ;; no-ns sentinel is #f — matches emit's quoted-symbol lowering
+         ;; (jolt-symbol #f "x"), so (= 'x (symbol "x")) holds (jolt= compares
+         ;; ns with strict equal?).
          ((string? a)
           (let ((slen (string-length a)))
             (if (string=? a "/")
                 (jolt-symbol #f "/")
-                (let loop ((i (- slen 1)))
-                  (cond ((<= i 0) (jolt-symbol #f a))
+                (let loop ((i 1))
+                  (cond ((>= i slen) (jolt-symbol #f a))
                         ((char=? (string-ref a i) #\/)
                          (jolt-symbol (substring a 0 i) (substring a (+ i 1) slen)))
-                        (else (loop (- i 1))))))))
+                        (else (loop (+ i 1))))))))
          ((keyword? a) (jolt-symbol (keyword-t-ns a) (keyword-t-name a)))
          ;; (symbol a-var) -> the var's qualified symbol (clojure.spec.alpha/->sym).
          ((var-cell? a) (jolt-symbol (var-cell-ns a) (var-cell-name a)))
@@ -155,7 +156,12 @@
 ;; int/long: truncate toward zero to an EXACT integer (= JVM long). char -> code
 ;; point (exact). double: always a flonum (= JVM double).
 (define (jolt-int x) (if (char? x) (char->integer x) (exact (truncate x))))
-(define (jolt-double x) (if (char? x) (exact->inexact (char->integer x)) (exact->inexact x)))
+;; a numeric type outside Chez's tower converts through this hook (bigdec).
+(define (jolt-double-slow x) (jolt-num-cast-throw x))
+(define (jolt-double x)
+  (cond ((char? x) (exact->inexact (char->integer x)))
+        ((number? x) (exact->inexact x))
+        (else (jolt-double-slow x))))
 
 ;; compare: 3-way, returns an EXACT integer (= JVM compare -> int).
 (define (jolt-cmp3 x y) (cond ((< x y) -1) ((> x y) 1) (else 0)))
@@ -172,7 +178,11 @@
     ((jolt-nil? b) 1)
     ((and (number? a) (number? b)) (jolt-cmp3 a b))
     ((and (string? a) (string? b)) (jolt-strcmp a b))
-    ((and (keyword? a) (keyword? b)) (jolt-strcmp (jolt-kw->string a) (jolt-kw->string b)))
+    ;; keywords order like symbols: a nil namespace sorts before any namespace,
+    ;; then by namespace, then by name (Keyword.compareTo -> Symbol.compareTo)
+    ((and (keyword? a) (keyword? b))
+     (let ((r (jolt-strcmp (or (keyword-t-ns a) "") (or (keyword-t-ns b) ""))))
+       (if (= r 0) (jolt-strcmp (keyword-t-name a) (keyword-t-name b)) r)))
     ((and (jolt-symbol? a) (jolt-symbol? b))
      (let ((r (jolt-strcmp (jolt-sym-ns-string a) (jolt-sym-ns-string b))))
        (if (= r 0) (jolt-strcmp (symbol-t-name a) (symbol-t-name b)) r)))
@@ -195,16 +205,84 @@
 (def-var! "clojure.core" "keyword" jolt-keyword)
 (def-var! "clojure.core" "symbol" jolt-symbol-new)
 (def-var! "clojure.core" "gensym" jolt-gensym)
-(def-var! "clojure.core" "int" jolt-int)
-;; char: coerce a code point (jolt's all-flonum number) to a Chez char; pass a
-;; char through. Inverse of int on chars. The cross-compiled emitter's
-;; chez-str-lit needs it for printable-ASCII escaping.
-(define (jolt-char x) (if (char? x) x (integer->char (exact (round x)))))
+;; --- checked narrow casts (RT.byteCast/shortCast/intCast/longCast/charCast) --
+;; One helper carries the JVM ranges: truncate toward zero, then range-check.
+;; NaN casts to 0 (Java (long)NaN); an out-of-range value (including a float
+;; infinity) is IllegalArgumentException "Value out of range for <type>: x".
+;; A non-numeric operand is the usual ClassCastException. Numeric types outside
+;; Chez's tower truncate through a hook the shim extends (BigDecimal).
+(define (jolt-cast-range-throw name x)
+  (jolt-throw (jolt-host-throwable
+               "java.lang.IllegalArgumentException"
+               (string-append "Value out of range for " name ": " (jolt-str x)))))
+(define (jolt-cast-truncate-slow x) (jolt-num-cast-throw x))
+(define (jolt-checked-cast name lo hi x)
+  (let ((n (cond ((char? x) (char->integer x))
+                 ((and (number? x) (exact? x)) (truncate x))
+                 ;; a double range-checks ITSELF (before truncation): (byte
+                 ;; 127.000001) throws, (byte 1.1) is 1; NaN casts to 0; an
+                 ;; infinity always fails the compare.
+                 ((flonum? x) (cond ((nan? x) 0)
+                                    ((or (< x lo) (> x hi)) (+ hi 1))
+                                    (else (exact (truncate x)))))
+                 (else (jolt-cast-truncate-slow x)))))
+    (if (and (>= n lo) (<= n hi)) n (jolt-cast-range-throw name x))))
+(define (jolt-byte-cast x)  (jolt-checked-cast "byte" -128 127 x))
+(define (jolt-short-cast x) (jolt-checked-cast "short" -32768 32767 x))
+(define (jolt-int-cast x)   (jolt-checked-cast "int" -2147483648 2147483647 x))
+(define (jolt-long-cast x)  (jolt-checked-cast "long" -9223372036854775808 9223372036854775807 x))
+(def-var! "clojure.core" "int" jolt-int-cast)
+(def-var! "clojure.core" "long" jolt-long-cast)
+(def-var! "clojure.core" "byte" jolt-byte-cast)
+(def-var! "clojure.core" "short" jolt-short-cast)
+;; char: pass a char through; a code point must be in [0, 0xFFFF] (charCast).
+(define (jolt-char x)
+  (if (char? x) x (integer->char (jolt-checked-cast "char" 0 65535 x))))
 (def-var! "clojure.core" "char" jolt-char)
-;; long: same truncation as int in jolt's all-flonum model (seed core-long =
-;; math/trunc; char -> code point). Distinct cell so (long ...) resolves.
-(def-var! "clojure.core" "long" jolt-int)
+;; unchecked-long: truncate + wrap to 64 bits (RT.uncheckedLongCast — a float
+;; infinity saturates, NaN is 0). unchecked-int wraps and sign-folds to 32.
+(define (jolt-cast-saturate n lo hi) (cond ((< n lo) lo) ((> n hi) hi) (else n)))
+(define (jolt-unchecked-long x)
+  (cond ((char? x) (char->integer x))
+        ;; an exact integer wraps (long narrowing); a double SATURATES (Java's
+        ;; double->long conversion clamps at the bounds, NaN is 0).
+        ((and (number? x) (exact? x)) (jolt-wrap64 (truncate x)))
+        ((flonum? x) (if (nan? x) 0
+                         (jolt-cast-saturate (if (infinite? x) (if (> x 0.0) unc-2^63 (- unc-2^63)) (exact (truncate x)))
+                                             -9223372036854775808 9223372036854775807)))
+        (else (jolt-wrap64 (jolt-cast-truncate-slow x)))))
+(define (jolt-unchecked-int x)
+  (if (flonum? x)
+      ;; double->int clamps like Java
+      (if (nan? x) 0
+          (jolt-cast-saturate (if (infinite? x) (if (> x 0.0) #x80000000 (- #x80000000)) (exact (truncate x)))
+                              -2147483648 2147483647))
+      (let ((i (bitwise-and (jolt-unchecked-long x) #xffffffff)))
+        (if (>= i #x80000000) (- i #x100000000) i))))
+(def-var! "clojure.core" "unchecked-long" jolt-unchecked-long)
+(def-var! "clojure.core" "unchecked-int" jolt-unchecked-int)
 (def-var! "clojure.core" "double" jolt-double)
-;; float: Chez has no single-float type, so float coerces to a flonum like double.
-(def-var! "clojure.core" "float" jolt-double)
+;; float: Chez has no single-float type, so the value stays a flonum — but the
+;; cast range-checks against Float/MAX_VALUE like RT.floatCast (an infinity is
+;; out of range; NaN passes).
+(define fl-float-max 3.4028234663852886e38)
+(define (jolt-float x)
+  (let ((d (jolt-double x)))
+    (if (and (flonum? d) (not (nan? d))
+             (or (< d (- fl-float-max)) (> d fl-float-max)))
+        (jolt-cast-range-throw "float" x)
+        d)))
+(def-var! "clojure.core" "float" jolt-float)
+;; numerator/denominator: jolt ratios are Chez exact rationals; a non-ratio is
+;; the JVM's Ratio cast failure.
+(define (jolt-ratio-part name f)
+  (lambda (x)
+    (if (and (number? x) (exact? x) (rational? x) (not (integer? x)))
+        (f x)
+        (jolt-throw (jolt-host-throwable
+                     "java.lang.ClassCastException"
+                     (string-append "class " (guard (e (#t "?")) (jolt-class-name x))
+                                    " cannot be cast to class clojure.lang.Ratio"))))))
+(def-var! "clojure.core" "numerator" (jolt-ratio-part "numerator" numerator))
+(def-var! "clojure.core" "denominator" (jolt-ratio-part "denominator" denominator))
 (def-var! "clojure.core" "compare" jolt-compare)

host/chez/dyn-binding.ss

@@ -77,14 +77,23 @@
       (let ((p (dyn-find-binding v)))
         (if p
             (begin (set-cdr! p val) val)
-            (begin (var-cell-root-set! v val) (var-cell-defined?-set! v #t) val)))
+            ;; a ROOT change is Var.bindRoot: validate, set, notify watches
+            ;; (a thread-binding set does not notify, like the JVM).
+            (let ((old (var-cell-root v)))
+              (iref-validate v val)
+              (var-cell-root-set! v val) (var-cell-defined?-set! v #t)
+              (iref-notify v old val)
+              val)))
       (error #f "var-set: not a var" v)))
 
 ;; alter-var-root: atomically apply f to the current root plus args.
 (define (jolt-alter-var-root v f . args)
-  (let ((new (apply jolt-invoke f (var-cell-root v) args)))
+  (let* ((old (var-cell-root v))
+         (new (apply jolt-invoke f old args)))
+    (iref-validate v new)
     (var-cell-root-set! v new)
     (var-cell-defined?-set! v #t)
+    (iref-notify v old new)
     new))
 
 ;; __local-var: a fresh free-standing var cell (not interned). with-local-vars

host/chez/emit-image.ss

@@ -46,6 +46,10 @@
 ;; after it). Guarded for the first re-mint pass off an older seed.
 (let ((scv (var-deref "jolt.backend-scheme" "set-var-cache!")))
   (when (procedure? scv) (scv #f)))
+;; Tail-frame tracing off for the mint + `jolt build`: the seed must stay a
+;; byte-fixpoint, and a built app should carry no per-call trace overhead.
+(let ((stf (var-deref "jolt.backend-scheme" "set-trace-frames!")))
+  (when (procedure? stf) (stf #f)))
 (define (ei-compile-form ctx f optimize?)
   (let ((ir (jolt-ce-analyze ctx f)))
     (jolt-ce-emit-top (if optimize? (jolt-ce-run-passes ir ctx) ir))))

host/chez/java/bigdec.ss

@@ -7,21 +7,19 @@
 ;;
 ;; Arithmetic follows java.math.BigDecimal's scale rules: add/sub align to the
 ;; larger scale; multiply adds scales; divide gives the exact quotient at minimal
-;; scale or throws ArithmeticException on a non-terminating expansion. Clojure
-;; contagion: a bigdec mixed with an integer stays a bigdec; a flonum operand wins
-;; (the result is a double). jbd-add/-sub/-mul/-div, jbd-min/-max, the jbd-lt?/…
-;; /zero? helpers, and jbd-quot/-rem are the shared engine. Two paths reach it, both
-;; leaving the inlined native hot path untouched:
-;;   - value position ((reduce + bigs)/(apply * bigs)): the jolt-add/-sub/-mul/-div
-;;     and compare shims dispatch here when a bigdec operand is present.
-;;   - call position ((+ 1.5M 2.5M), (< a b), (zero? b)): jolt.passes.numeric tags
-;;     the invoke :num-kind :bigdec when every operand is statically a bigdec (M
-;;     literal or a let-bound copy, integer literals allowed), and the back end
-;;     lowers it to the jbd op. Non-bigdec code is unaffected.
-;; Gaps (a runtime bigdec the analyzer can't see statically): a bigdec mixed with a
-;; flonum in call position ((+ 1.5M 2.0)) and arithmetic over a bigdec the analyzer
-;; types as :any ((+ (bigdec x) 1)) fall through to the raw op and throw; use value
-;; position or a literal-typed let.
+;; scale or throws ArithmeticException on a non-terminating expansion (a bound
+;; *math-context* rounds instead). Clojure contagion: a bigdec mixed with an
+;; integer or ratio stays a bigdec; a flonum operand wins (the result is a
+;; double). jbd-add/-sub/-mul/-div, jbd-min/-max, the jbd-lt?/…/zero? helpers,
+;; and jbd-quot/-rem are the shared engine. Two paths reach it, both leaving the
+;; inlined fast path untouched:
+;;   - the seq.ss binary dispatch: every generic op (any position — (+ (bigdec x)
+;;     1), (reduce + bigs), (quot 10.0 3M)) whose operand is outside Chez's tower
+;;     falls to the jolt-*-slow hooks extended below.
+;;   - static call position ((+ 1.5M 2.5M), (< a b), (zero? b)): jolt.passes.numeric
+;;     tags the invoke :num-kind :bigdec when every operand is statically a bigdec
+;;     (M literal or a let-bound copy, integer literals allowed), and the back end
+;;     lowers it directly to the jbd op.
 
 (define-record-type jbigdec (fields unscaled scale) (nongenerative chez-jbigdec-v1))
 
@@ -79,11 +77,13 @@
 (define (jbigdec->flonum b)
   (exact->inexact (/ (jbigdec-unscaled b) (expt 10 (jbigdec-scale b)))))
 
-;; coerce an exact integer to a scale-0 bigdec; pass a bigdec through. Used on the
-;; non-flonum mixed path (bigdec + long -> bigdec).
+;; coerce an exact operand to a bigdec; pass a bigdec through. Used on the
+;; non-flonum mixed path (bigdec + long -> bigdec). A Ratio converts like
+;; Numbers.toBigDecimal — exact decimal expansion or throw on non-terminating.
 (define (jbd-coerce x)
   (cond ((jbigdec? x) x)
         ((and (number? x) (exact? x) (integer? x)) (make-jbigdec x 0))
+        ((and (number? x) (exact? x) (rational? x)) (jbd-rational->bigdec x))
         (else (error #f "bigdec arithmetic: cannot coerce operand" x))))
 
 ;; --- core arithmetic on the {unscaled, scale} pair --------------------------
@@ -117,12 +117,39 @@
                            "java.lang.ArithmeticException"
                            "Non-terminating decimal expansion; no exact representable decimal result.")))))))
 
+;; floor(log10 |r|) for a nonzero exact rational.
+(define (jbd-exp10 r)
+  (let ((n (abs (numerator r))) (d (denominator r)))
+    (if (>= n d)
+        (- (jbd-digits (quotient n d)) 1)
+        (let loop ((x (* n 10)) (e -1))
+          (if (>= x d) e (loop (* x 10) (- e 1)))))))
+;; round an exact rational to `prec` significant digits (the MathContext divide).
+(define (jbd-rational-prec r prec mode)
+  (if (= r 0)
+      (make-jbigdec 0 0)
+      (let* ((neg (< r 0)) (ar (abs r))
+             (s (- prec 1 (jbd-exp10 ar)))
+             (scaled (* ar (expt 10 s)))
+             (q (floor scaled)) (frac (- scaled q))
+             (q2 (if (jbd-round-inc? q frac 1 mode neg) (+ q 1) q))
+             (res (make-jbigdec (if neg (- q2) q2) s)))
+        ;; a carry can add a digit (9.99 -> 10.0); re-normalizing drops an exact
+        ;; trailing zero, never re-rounds.
+        (if (> (jbd-digits q2) prec) (jbd-round-prec res prec mode) res))))
+
 (define (jbd2-div a b)
   (when (= 0 (jbigdec-unscaled b))
     (jolt-throw (jolt-host-throwable "java.lang.ArithmeticException" "Divide by zero")))
-  ;; a/b = (ua * 10^sb) / (ub * 10^sa) as an exact rational.
-  (jbd-rational->bigdec (/ (* (jbigdec-unscaled a) (expt 10 (jbigdec-scale b)))
-                           (* (jbigdec-unscaled b) (expt 10 (jbigdec-scale a))))))
+  ;; a/b = (ua * 10^sb) / (ub * 10^sa) as an exact rational. Unlimited context:
+  ;; exact result at minimal scale or throw on a non-terminating expansion. A
+  ;; bound *math-context* instead rounds to its precision.
+  (let ((r (/ (* (jbigdec-unscaled a) (expt 10 (jbigdec-scale b)))
+              (* (jbigdec-unscaled b) (expt 10 (jbigdec-scale a)))))
+        (mc (jbd-math-context)))
+    (if mc
+        (jbd-rational-prec r (jbd-mc-precision mc) (jbd-mc-mode mc))
+        (jbd-rational->bigdec r))))
 
 ;; integer-division semantics (quot/rem): truncate toward zero, scale 0.
 (define (jbd-int-quot a b)
@@ -139,13 +166,65 @@
 (define (jbd-compare2 a b)
   (let-values (((ua ub s) (jbd-align a b))) (cond ((< ua ub) -1) ((> ua ub) 1) (else 0))))
 
+;; --- *math-context* (with-precision) -----------------------------------------
+;; with-precision binds clojure.core/*math-context* to {:precision N :rounding
+;; MODE}; every exact bigdec result rounds through it (java.math.MathContext).
+(define jbd-kw-precision (keyword #f "precision"))
+(define jbd-kw-rounding (keyword #f "rounding"))
+(define (jbd-math-context)
+  (let ((mc (var-deref "clojure.core" "*math-context*")))
+    (if (jolt-nil? mc) #f mc)))
+(define (jbd-mc-precision mc) (jolt-get mc jbd-kw-precision))
+(define (jbd-mc-mode mc)
+  (let ((r (jolt-get mc jbd-kw-rounding)))
+    (cond ((symbol-t? r) (symbol-t-name r))
+          ((string? r) r)
+          (else "HALF_UP"))))
+
+;; should |value| = q + r/div (0 <= r < div) round up in magnitude? neg is the
+;; value's sign; r/div may be exact rationals (the division path).
+(define (jbd-round-inc? q r div mode neg)
+  (cond ((= r 0) #f)
+        ((string=? mode "UP") #t)
+        ((string=? mode "DOWN") #f)
+        ((string=? mode "CEILING") (not neg))
+        ((string=? mode "FLOOR") neg)
+        ((string=? mode "HALF_DOWN") (> (* 2 r) div))
+        ((string=? mode "HALF_EVEN")
+         (let ((c (- (* 2 r) div)))
+           (cond ((> c 0) #t) ((< c 0) #f) (else (odd? q)))))
+        ((string=? mode "UNNECESSARY")
+         (jolt-throw (jolt-host-throwable "java.lang.ArithmeticException" "Rounding necessary")))
+        (else (>= (* 2 r) div))))     ; HALF_UP, the MathContext default
+
+(define (jbd-digits n) (string-length (number->string (abs n))))
+;; round a bigdec to `prec` significant digits with `mode` (a RoundingMode name).
+(define (jbd-round-prec bd prec mode)
+  (let ((u (jbigdec-unscaled bd)) (s (jbigdec-scale bd)))
+    (if (= u 0)
+        bd
+        (let ((digs (jbd-digits u)))
+          (if (<= digs prec)
+              bd
+              (let* ((drop (- digs prec)) (div (expt 10 drop))
+                     (neg (< u 0)) (au (abs u))
+                     (q (quotient au div)) (r (remainder au div))
+                     (q2 (if (jbd-round-inc? q r div mode neg) (+ q 1) q))
+                     (res (make-jbigdec (if neg (- q2) q2) (- s drop))))
+                ;; a carry can add a digit back (99 -> 100 at precision 2)
+                (if (> (jbd-digits q2) prec) (jbd-round-prec res prec mode) res)))))))
+(define (jbd-mc-round x)
+  (let ((mc (and (jbigdec? x) (jbd-math-context))))
+    (if mc (jbd-round-prec x (jbd-mc-precision mc) (jbd-mc-mode mc)) x)))
+
 ;; A binary op over operands that may mix bigdec / integer / flonum. flonum-op is
-;; the native fallback for the double-contagion path; bd-op is the exact bigdec op.
+;; the native fallback for the double-contagion path; bd-op is the exact bigdec op
+;; (its result rounds through a bound *math-context*).
 (define (jbd-binop flonum-op bd-op a b)
   (if (or (flonum? a) (flonum? b))
       (flonum-op (if (jbigdec? a) (jbigdec->flonum a) a)
                  (if (jbigdec? b) (jbigdec->flonum b) b))
-      (bd-op (jbd-coerce a) (jbd-coerce b))))
+      (jbd-mc-round (bd-op (jbd-coerce a) (jbd-coerce b)))))
 
 ;; --- variadic engine ops (Phase-2 emit targets + value-position folds) -------
 (define (jbd-fold flonum-op bd-op init xs)
@@ -203,23 +282,96 @@
 ;; --- wire into the value model ----------------------------------------------
 (def-var! "clojure.core" "bigdec" jolt-bigdec)
 
-;; Value-position arithmetic: (reduce + bigs) / (apply * bigs) pass +/*/- // AS A
-;; VALUE, which lowers to these shims (NOT the inlined hot-path native op). Extend
-;; them to dispatch to the bigdec engine when a bigdec operand is present; ordinary
-;; numeric folds hit the captured native path unchanged.
-(define jbd-prev-add jolt-add)
-(define jbd-prev-sub jolt-sub)
-(define jbd-prev-mul jolt-mul)
-(define jbd-prev-div jolt-div)
-(define jbd-prev-min jolt-min)
-(define jbd-prev-max jolt-max)
-(define (jbd-any? xs) (and (pair? xs) (or (jbigdec? (car xs)) (jbd-any? (cdr xs)))))
-(set! jolt-add (lambda xs (if (jbd-any? xs) (apply jbd-add xs) (apply jbd-prev-add xs))))
-(set! jolt-sub (lambda xs (if (jbd-any? xs) (apply jbd-sub xs) (apply jbd-prev-sub xs))))
-(set! jolt-mul (lambda xs (if (jbd-any? xs) (apply jbd-mul xs) (apply jbd-prev-mul xs))))
-(set! jolt-div (lambda xs (if (jbd-any? xs) (apply jbd-div xs) (apply jbd-prev-div xs))))
-(set! jolt-min (lambda xs (if (jbd-any? xs) (apply jbd-min xs) (apply jbd-prev-min xs))))
-(set! jolt-max (lambda xs (if (jbd-any? xs) (apply jbd-max xs) (apply jbd-prev-max xs))))
+;; The seq.ss binary numeric dispatch (jolt-add2/… and the jolt-n* macros) routes
+;; any op whose operand is outside Chez's tower to the *-slow hooks; extend each
+;; with a bigdec arm. Every arithmetic position (call, value, higher-order)
+;; funnels through these, so contagion and *math-context* rounding apply
+;; uniformly. min/max need no arm: the generic jolt-min2 compares through
+;; jolt-num-cmp-slow and returns the original operand.
+(set! jolt-num-slow?
+  (let ((prev jolt-num-slow?)) (lambda (x) (or (jbigdec? x) (prev x)))))
+(define (jbd-extend-hook prev bd-op)
+  (lambda (a b)
+    (if (or (jbigdec? a) (jbigdec? b)) (bd-op a b) (prev a b))))
+(set! jolt-add-slow (jbd-extend-hook jolt-add-slow (lambda (a b) (jbd-binop + jbd2+ a b))))
+(set! jolt-sub-slow (jbd-extend-hook jolt-sub-slow (lambda (a b) (jbd-binop - jbd2- a b))))
+(set! jolt-mul-slow (jbd-extend-hook jolt-mul-slow (lambda (a b) (jbd-binop * jbd2* a b))))
+(set! jolt-div-slow (jbd-extend-hook jolt-div-slow (lambda (a b) (jbd-binop / jbd2-div a b))))
+(set! jolt-num-cmp-slow
+  (let ((prev jolt-num-cmp-slow))
+    (lambda (a b)
+      (if (and (or (jbigdec? a) (jbigdec? b)) (jbd-numberish? a) (jbd-numberish? b))
+          (jbd-value-compare a b)
+          (prev a b)))))
+;; quot/rem/mod: a double operand demotes to the double path; exact operands use
+;; the integer-division bigdec ops (mod = rem, floor-adjusted to the divisor's sign).
+(define (jbd->num x) (if (jbigdec? x) (jbigdec->flonum x) x))
+(set! jolt-quot-slow
+  (jbd-extend-hook jolt-quot-slow
+    (lambda (a b) (if (or (flonum? a) (flonum? b))
+                      (jolt-quot (jbd->num a) (jbd->num b))
+                      (jbd-int-quot (jbd-coerce a) (jbd-coerce b))))))
+(set! jolt-rem-slow
+  (jbd-extend-hook jolt-rem-slow
+    (lambda (a b) (if (or (flonum? a) (flonum? b))
+                      (jolt-rem (jbd->num a) (jbd->num b))
+                      (jbd-int-rem (jbd-coerce a) (jbd-coerce b))))))
+(set! jolt-mod-slow
+  (jbd-extend-hook jolt-mod-slow
+    (lambda (a b)
+      (if (or (flonum? a) (flonum? b))
+          (jolt-mod (jbd->num a) (jbd->num b))
+          (let* ((bb (jbd-coerce b))
+                 (m (jbd-int-rem (jbd-coerce a) bb)))
+            (if (or (jbd-zero? m) (eq? (jbd-neg? m) (jbd-neg? bb))) m (jbd2+ m bb)))))))
+;; unary shims: inc/dec and the sign predicates take a bigdec arm. set! updates
+;; call-position references; the re-def-var! updates the var cell AND claims the
+;; wrapped proc's class name before the prelude's inc'/dec' aliases are defined
+;; ((type inc) stays clojure.core$inc — first def wins in the class registry).
+(define jbd-one (make-jbigdec 1 0))
+(set! jolt-inc (let ((prev jolt-inc)) (lambda (x) (if (jbigdec? x) (jbd-mc-round (jbd2+ x jbd-one)) (prev x)))))
+(set! jolt-dec (let ((prev jolt-dec)) (lambda (x) (if (jbigdec? x) (jbd-mc-round (jbd2- x jbd-one)) (prev x)))))
+(set! jolt-zero? (let ((prev jolt-zero?)) (lambda (x) (if (jbigdec? x) (jbd-zero? x) (prev x)))))
+(set! jolt-pos? (let ((prev jolt-pos?)) (lambda (x) (if (jbigdec? x) (jbd-pos? x) (prev x)))))
+(set! jolt-neg? (let ((prev jolt-neg?)) (lambda (x) (if (jbigdec? x) (jbd-neg? x) (prev x)))))
+;; a BigDecimal IS a number (java.lang.Number): extend the number? native so the
+;; predicate — and everything defined over it (num, =='s guard) — accepts it.
+;; The compiled fast paths test Chez number? directly and are unaffected.
+(set! jolt-number? (let ((prev jolt-number?)) (lambda (x) (if (jbigdec? x) #t (prev x)))))
+(def-var! "clojure.core" "number?" jolt-number?)
+(def-var! "clojure.core" "inc" jolt-inc)
+(def-var! "clojure.core" "dec" jolt-dec)
+(def-var! "clojure.core" "zero?" jolt-zero?)
+(def-var! "clojure.core" "pos?" jolt-pos?)
+(def-var! "clojure.core" "neg?" jolt-neg?)
+
+;; rationalize: reference Clojure goes through BigDecimal.valueOf(double) — the
+;; SHORTEST decimal print of the double, not its exact binary value — so
+;; (rationalize 1.1) is 11/10. A bigdec is exact already; other exacts pass through.
+(define (jolt-rationalize x)
+  (cond ((jbigdec? x) (/ (jbigdec-unscaled x) (expt 10 (jbigdec-scale x))))
+        ((flonum? x)
+         (if (or (nan? x) (infinite? x))
+             (jolt-throw (jolt-host-throwable "java.lang.NumberFormatException"
+                                              (string-append "Invalid input: " (number->string x))))
+             (let ((bd (jolt-bigdec-from-string (jolt-num->string x))))
+               (/ (jbigdec-unscaled bd) (expt 10 (jbigdec-scale bd))))))
+        ((number? x) x)
+        (else (jolt-num-cast-throw x))))
+(def-var! "clojure.core" "rationalize" jolt-rationalize)
+
+;; double/float of a bigdec is its flonum value.
+(set! jolt-double-slow
+  (let ((prev jolt-double-slow))
+    (lambda (x) (if (jbigdec? x) (jbigdec->flonum x) (prev x)))))
+
+;; narrow casts truncate a bigdec like Number.longValue.
+(set! jolt-cast-truncate-slow
+  (let ((prev jolt-cast-truncate-slow))
+    (lambda (x)
+      (if (jbigdec? x)
+          (truncate (/ (jbigdec-unscaled x) (expt 10 (jbigdec-scale x))))
+          (prev x)))))
 
 ;; compare: add a bigdec arm (enables compare / sort / sorted collections). A
 ;; bigdec vs a plain number compares by value; bigdec vs bigdec is scale-independent.

host/chez/java/class-hierarchy.ss

@@ -33,6 +33,15 @@
 
 (define (jch-direct-supers name) (hashtable-ref jvm-class-parents name '()))
 
+;; Replace a class's direct supers outright (defrecord re-declares the row its
+;; deftype half registered). Same cache invalidation as a register.
+(define (jch-set-supers! name supers)
+  (hashtable-set! jvm-class-parents name supers)
+  (hashtable-clear! jch-closure-cache)
+  (hashtable-clear! jch-tags-cache)
+  (set! jch-known-cache #f)
+  (set! jch-simple->fqn-cache #f))
+
 ;; transitive supers of NAME (canonical), excluding NAME and Object; Object is the
 ;; universal root supplied by callers. Breadth-first, deduped, stable order.
 (define (jch-closure name)
@@ -46,6 +55,11 @@
         (hashtable-set! jch-closure-cache name result)
         result)))
 
+;; ns segment munging for a JVM-spelled class name: dashes become underscores
+;; (clojure.core-test.x -> clojure.core_test.x).
+(define (jch-munge-segments s)
+  (list->string (map (lambda (c) (if (char=? c #\-) #\_ c)) (string->list s))))
+
 (define (jch-last-segment s)
   (let loop ((i (- (string-length s) 1)))
     (cond ((< i 0) s)
@@ -130,6 +144,30 @@
     (set! jch-simple->fqn-cache #f)
     (jch-register-supers!-inner name supers)))
 
+;; ---- interface marking ---------------------------------------------------------
+;; The JVM distinguishes a concrete class (whose bases/supers chain roots at
+;; Object) from an interface (whose don't). The graph marks the modeled
+;; interfaces; anything unmarked is treated as a concrete class.
+(define jch-interface-set (make-hashtable string-hash string=?))
+(define (jch-mark-interface! name) (hashtable-set! jch-interface-set name #t))
+(define (jch-interface? name) (hashtable-ref jch-interface-set name #f))
+(for-each jch-mark-interface!
+          '("clojure.lang.Seqable" "clojure.lang.Sequential" "clojure.lang.Sorted"
+            "clojure.lang.Reversible" "clojure.lang.Indexed" "clojure.lang.Counted"
+            "clojure.lang.Named" "clojure.lang.Fn" "clojure.lang.IFn"
+            "clojure.lang.IPersistentCollection" "clojure.lang.ISeq"
+            "clojure.lang.Associative" "clojure.lang.ILookup"
+            "clojure.lang.IPersistentStack" "clojure.lang.IPersistentVector"
+            "clojure.lang.IPersistentMap" "clojure.lang.IPersistentSet"
+            "clojure.lang.IPersistentList" "clojure.lang.IObj" "clojure.lang.IMeta"
+            "clojure.lang.IDeref" "clojure.lang.IRecord" "clojure.lang.IType"
+            "clojure.lang.IHashEq" "clojure.lang.IEditableCollection"
+            "clojure.lang.IExceptionInfo" "clojure.lang.IReduceInit"
+            "java.util.List" "java.util.Set" "java.util.Collection" "java.util.Map"
+            "java.util.Iterator" "java.lang.Iterable" "java.lang.CharSequence"
+            "java.lang.Comparable" "java.lang.Runnable"
+            "java.util.concurrent.Callable" "java.io.Serializable"))
+
 ;; ---- seed the built-in graph: direct supers only, faithful to the JVM ---------
 ;; core clojure.lang interfaces
 (jch-register-supers! "clojure.lang.IPersistentCollection" '("clojure.lang.Seqable"))

host/chez/java/concurrency.ss

@@ -151,16 +151,31 @@
           (mutable queue) (mutable running?) mu cv)
   (nongenerative jolt-agent-v1))
 
-;; (agent state) / (agent state :validator f :error-mode m :meta x): only :validator
-;; has runtime behaviour here; other opts are accepted/ignored.
+;; (agent state :meta m :validator f :error-mode e): the ARef ctor contract like
+;; atom's — the validator runs against the initial state, :meta must be a map.
+;; :error-mode is accepted/ignored (jolt agents are always :fail).
 (define (jolt-agent-new state . opts)
-  (let loop ((o opts) (validator jolt-nil))
+  (let loop ((o opts) (validator jolt-nil) (m #f))
     (cond
       ((or (null? o) (null? (cdr o)))
-       (make-jolt-agent state jolt-nil validator (vector '() '()) #f (make-mutex) (make-condition)))
+       (let ((a (make-jolt-agent state jolt-nil validator (vector '() '()) #f (make-mutex) (make-condition))))
+         (when (and (not (jolt-nil? validator)) (jolt-not (jolt-invoke validator state)))
+           (jolt-iref-state-throw))
+         (when (and m (not (jolt-nil? m)))
+           (unless (jolt-map? m)
+             (jolt-throw (jolt-host-throwable
+                          "java.lang.ClassCastException"
+                          (string-append "class " (jolt-class-name m)
+                                         " cannot be cast to class clojure.lang.IPersistentMap"))))
+           (hashtable-set! meta-table a m))
+         a))
       ((and (keyword-t? (car o)) (string=? (keyword-t-name (car o)) "validator"))
-       (loop (cddr o) (cadr o)))
-      (else (loop (cddr o) validator)))))
+       (loop (cddr o) (cadr o) m))
+      ((and (keyword-t? (car o)) (string=? (keyword-t-name (car o)) "meta"))
+       (loop (cddr o) validator (cadr o)))
+      (else (loop (cddr o) validator m)))))
+;; agents are watchable IRefs; the worker notifies on each state change.
+(register-iref-arm! jolt-agent?)
 
 ;; The action queue is an amortized-O(1) FIFO held as a mutable #(out in): `out` is
 ;; the front, `in` holds sends reversed onto it (an append-to-a-list send was O(n)).
@@ -189,11 +204,13 @@
         (guard (e (#t (with-mutex (jolt-agent-mu a)
                         (jolt-agent-err-set! a e)
                         (condition-broadcast (jolt-agent-cv a)))))
-          (let ((nv (apply jolt-invoke (car act) (jolt-agent-state a) (cdr act))))
+          (let* ((old (jolt-agent-state a))
+                 (nv (apply jolt-invoke (car act) old (cdr act))))
             (let ((vf (jolt-agent-validator a)))
               (when (and (not (jolt-nil? vf)) (jolt-not (jolt-invoke vf nv)))
-                (error #f "Invalid reference state")))
-            (jolt-agent-state-set! a nv)))
+                (jolt-iref-state-throw)))
+            (jolt-agent-state-set! a nv)
+            (iref-notify a old nv)))
         (loop)))))
 
 ;; send / send-off: enqueue the action, start the worker if idle. (jolt treats them
@@ -284,6 +301,16 @@
 (def-var! "clojure.core" "future-cancelled?" jolt-native-future-cancelled?)
 (def-var! "clojure.core" "promise" jolt-promise-new)
 (def-var! "clojure.core" "deliver" jolt-deliver)
+;; a promise is an IFn on the JVM: (p val) delivers. Registered as a cold
+;; invoke arm; callable-host? feeds the ifn? overlay (multimethods included).
+(register-invoke-arm! jolt-promise?
+  (lambda (p args)
+    (if (and (pair? args) (null? (cdr args)))
+        (jolt-deliver p (car args))
+        (jolt-throw (jolt-host-throwable "clojure.lang.ArityException"
+                                         "Wrong number of args passed to a promise")))))
+(def-var! "jolt.host" "callable-host?"
+  (lambda (x) (if (or (jolt-multifn? x) (jolt-promise? x)) #t jolt-nil)))
 (def-var! "clojure.core" "agent" jolt-agent-new)
 (def-var! "clojure.core" "agent?" jolt-agent?)
 (def-var! "clojure.core" "send" jolt-agent-send)
@@ -552,9 +579,9 @@
 ;; pthread_sigmask"). Guard so a non-POSIX host yields #f; jolt-set-sigint-blocked
 ;; then no-ops (Windows delivers ^C through the console, not a per-thread mask).
 (define c-pthread-sigmask
-  (guard (e (#t #f)) (foreign-procedure "pthread_sigmask" (int u8* u8*) int)))
-(define c-sigemptyset (guard (e (#t #f)) (foreign-procedure "sigemptyset" (u8*) int)))
-(define c-sigaddset (guard (e (#t #f)) (foreign-procedure "sigaddset" (u8* int) int)))
+  (jolt-foreign-proc-safe "pthread_sigmask" '(int u8* u8*) 'int))
+(define c-sigemptyset (jolt-foreign-proc-safe "sigemptyset" '(u8*) 'int))
+(define c-sigaddset (jolt-foreign-proc-safe "sigaddset" '(u8* int) 'int))
 ;; POSIX SIG_BLOCK/SIG_UNBLOCK numerics differ by platform: Linux/glibc 0/1,
 ;; Darwin/macOS 1/2 (SIG_UNBLOCK is SIG_BLOCK+1 on both). Resolve SIG_BLOCK for
 ;; this host from the machine-type symbol — macOS builds contain "osx".

host/chez/java/dot-forms.ss

@@ -60,6 +60,12 @@
     ;; branch and is mis-read as a missing :iterator key (nil). Some libraries
     ;; (e.g. malli's -vmap) iterate a map this way.
     ((string=? name "iterator") (list (make-jiterator (jolt-seq obj))))
+    ;; (.reduce coll f) / (.reduce coll f init): clojure.lang.IReduce — every
+    ;; persistent collection reduces itself on the JVM.
+    ((string=? name "reduce")
+     (list (if (pair? (cdr args))
+               (jolt-reduce (car args) (cadr args) obj)
+               (jolt-reduce (car args) obj))))
     (else #f)))
 
 ;; Universal object-methods: on a

host/chez/java/host-static-classes.ss

@@ -841,7 +841,12 @@
 (define (make-class-obj name) (make-jhost "class" (vector name)))
 (define (jclass? x) (and (jhost? x) (string=? (jhost-tag x) "class")))
 (define (jclass-name x) (vector-ref (jhost-state x) 0))
-(define (class-key x) (cond ((jclass? x) (jclass-name x)) ((string? x) x) (else #f)))
+(define (class-key x)
+  (cond ((jclass? x) (jclass-name x))
+        ((string? x) x)
+        ;; a deftype/defrecord NAME var holds its ctor; treat it as the class
+        ((procedure? x) (hashtable-ref chez-deftype-ctor-tag x #f))
+        (else #f)))
 (register-eq-arm! (lambda (a b) (or (jclass? a) (jclass? b)))
                   (lambda (a b) (let ((ka (class-key a)) (kb (class-key b)))
                                   (and ka kb (string=? ka kb) #t))))
@@ -1047,19 +1052,62 @@
                 #t jolt-nil))
           jolt-nil))))
 
+;; is NAME a class the host models (registered in the class graph, a legacy
+;; supers-table entry, or a fn class)? Object itself is modeled.
+(define (hsc-class-known? name)
+  (or (string=? name "java.lang.Object")
+      (jch-known? name)
+      (and (hashtable-ref class-supers-tbl name #f) #t)
+      (str-has-dollar? name)))
+
+;; transitive ancestry, rooted at Object for a concrete class like (supers c);
+;; an interface's chain has no Object (its getSuperclass is null). '() for
+;; Object itself and for a name the host doesn't model.
+(define (class-ancestors-rooted name)
+  (if (or (string=? name "java.lang.Object") (jch-interface? name))
+      (class-ancestors-list name)
+      (let ((as (class-ancestors-list name)))
+        (cond ((member "java.lang.Object" as) as)
+              ((null? as) (if (hsc-class-known? name) '("java.lang.Object") '()))
+              (else (append as '("java.lang.Object")))))))
+
 ;; (jolt.host/class-supers name) / (jolt.host/class-ancestors name) — a jolt seq of
-;; super / ancestor class-name strings, or nil when jolt models no hierarchy for it.
+;; super / ancestor class-name strings (transitive, Object-rooted), or nil when
+;; jolt models no hierarchy for it. class-bases is the DIRECT supers (clojure.core
+;; `bases` / the class arm of `parents`).
 (def-var! "jolt.host" "class-supers"
   (lambda (x)
     (let ((name (class-key x)))
       (if name
-          (let ((as (class-ancestors-list name)))   ; transitive, like the JVM
+          (let ((as (class-ancestors-rooted name)))
             (if (null? as) jolt-nil (list->cseq as)))
           jolt-nil))))
 (def-var! "jolt.host" "class-ancestors"
   (lambda (x)
     (let ((name (class-key x)))
       (if name
-          (let ((as (class-ancestors-list name)))
+          (let ((as (class-ancestors-rooted name)))
             (if (null? as) jolt-nil (list->cseq as)))
           jolt-nil))))
+(def-var! "jolt.host" "class-bases"
+  (lambda (x)
+    (let ((name (class-key x)))
+      (if name
+          (let* ((ds (class-direct-supers name))
+                 ;; a concrete class's bases include its superclass — Object when
+                 ;; nothing more specific is modeled (interfaces have none).
+                 (ds (if (or (string=? name "java.lang.Object")
+                             (jch-interface? name)
+                             (member "java.lang.Object" ds))
+                         ds
+                         (append ds '("java.lang.Object")))))
+            (if (null? ds) jolt-nil (list->cseq ds)))
+          jolt-nil))))
+;; is X a class value — a jclass, a deftype ctor, or a name string the host
+;; graph models?
+(def-var! "jolt.host" "class-value?"
+  (lambda (x)
+    (if (jclass? x)
+        #t
+        (let ((n (class-key x)))
+          (if (and n (hsc-class-known? n)) #t jolt-nil)))))

host/chez/java/host-static-methods.ss

@@ -55,9 +55,7 @@
     (lambda ()
       (unless tried?
         (set! tried? #t)
-        (set! fp (guard (e (#t #f))
-                   (load-shared-object #f)
-                   (foreign-procedure "sched_yield" () int))))
+        (set! fp (jolt-foreign-proc-safe "sched_yield" '() 'int)))
       (if fp (fp) (sleep (make-time 'time-duration 0 0)))
       jolt-nil)))
 
@@ -202,7 +200,8 @@
                 (bitwise-ior (bitwise-arithmetic-shift-left r 1)
                              (bitwise-and (bitwise-arithmetic-shift-right v i) 1)))))))
 (register-class-statics! "Long"
-  (list (cons "MAX_VALUE" (->num 9223372036854775807))
+  (list (cons "TYPE" "long")
+        (cons "MAX_VALUE" (->num 9223372036854775807))
         (cons "MIN_VALUE" (->num -9223372036854775808))
         (cons "bitCount" (lambda (n) (->num (bitwise-bit-count (bitwise-and (jnum->exact n) long-mask64)))))
         (cons "numberOfLeadingZeros" (lambda (n) (->num (long-nlz n))))
@@ -214,6 +213,8 @@
 (define (int->u32 n) (if (< n 0) (+ n 4294967296) n))
 (register-class-statics! "Integer"
   (list (cons "MAX_VALUE" (->num 2147483647)) (cons "MIN_VALUE" (->num -2147483648))
+        ;; the primitive class token (int.class); jolt models a class as its name
+        (cons "TYPE" "int")
         (cons "valueOf" (lambda (x . r)
                           (if (number? x) (->num x)
                               (parse-int-or-throw x (if (null? r) 10 (jnum->exact (car r))) "valueOf"))))
@@ -227,12 +228,14 @@
 ;; Byte / Short bounds (their values are plain integers on jolt; the statics let
 ;; libraries reference the JVM ranges — clojure.test.check generates over them).
 (register-class-statics! "Byte"
-  (list (cons "MAX_VALUE" (->num 127)) (cons "MIN_VALUE" (->num -128))
+  (list (cons "TYPE" "byte")
+        (cons "MAX_VALUE" (->num 127)) (cons "MIN_VALUE" (->num -128))
         (cons "valueOf" (lambda (x . r) (->num (if (number? x) x (parse-int-or-throw x 10 "valueOf")))))
         (cons "parseByte" (lambda (x . r) (parse-int-or-throw x (if (null? r) 10 (jnum->exact (car r))) "parseByte")))
         (cons "toString" (lambda (x . r) (number->string (jnum->exact x))))))
 (register-class-statics! "Short"
-  (list (cons "MAX_VALUE" (->num 32767)) (cons "MIN_VALUE" (->num -32768))
+  (list (cons "TYPE" "short")
+        (cons "MAX_VALUE" (->num 32767)) (cons "MIN_VALUE" (->num -32768))
         (cons "valueOf" (lambda (x . r) (->num (if (number? x) x (parse-int-or-throw x 10 "valueOf")))))
         (cons "parseShort" (lambda (x . r) (parse-int-or-throw x (if (null? r) 10 (jnum->exact (car r))) "parseShort")))
         (cons "toString" (lambda (x . r) (number->string (jnum->exact x))))))
@@ -247,13 +250,15 @@
         (cons "ROOT" "und") (cons "US" "en-US") (cons "ENGLISH" "en")))
 
 (register-class-statics! "Boolean"
-  (list (cons "parseBoolean" (lambda (s) (string=? "true" (ascii-string-down (if (string? s) s (jolt-str-render-one s))))))
+  (list (cons "TYPE" "boolean")
+        (cons "parseBoolean" (lambda (s) (string=? "true" (ascii-string-down (if (string? s) s (jolt-str-render-one s))))))
         (cons "TRUE" #t) (cons "FALSE" #f)))
 
 (register-class-ctor! "Double" ->double)
 (register-class-ctor! "Float" ->double)
 (register-class-statics! "Double"
-  (list (cons "parseDouble" parse-double-or-throw)
+  (list (cons "TYPE" "double")
+        (cons "parseDouble" parse-double-or-throw)
         (cons "valueOf" ->double)
         (cons "toString" (lambda (x) (jolt-str-render-one (->double x))))
         (cons "isNaN" (lambda (x) (and (flonum? x) (nan? x))))
@@ -261,11 +266,13 @@
         (cons "MAX_VALUE" 1.7976931348623157e308) (cons "MIN_VALUE" 4.9e-324)
         (cons "POSITIVE_INFINITY" +inf.0) (cons "NEGATIVE_INFINITY" -inf.0) (cons "NaN" +nan.0)))
 (register-class-statics! "Float"
-  (list (cons "parseFloat" parse-double-or-throw) (cons "valueOf" ->double)))
+  (list (cons "TYPE" "float")
+        (cons "parseFloat" parse-double-or-throw) (cons "valueOf" ->double)))
 
 ;; Character: ASCII predicates (the engine is byte/ASCII oriented).
 (register-class-statics! "Character"
-  (list (cons "isUpperCase" (lambda (c) (let ((n (char-code c))) (and (>= n 65) (<= n 90)))))
+  (list (cons "TYPE" "char")
+        (cons "isUpperCase" (lambda (c) (let ((n (char-code c))) (and (>= n 65) (<= n 90)))))
         (cons "isLowerCase" (lambda (c) (let ((n (char-code c))) (and (>= n 97) (<= n 122)))))
         (cons "isDigit" (lambda (c) (let ((n (char-code c))) (and (>= n 48) (<= n 57)))))
         ;; JVM Character.isWhitespace: Unicode whitespace (so U+2028 line separator

host/chez/java/io.ss

@@ -80,13 +80,18 @@
 ;; every Chez binary) — no external toolchain. Falls back to /bin/sh chmod if the
 ;; symbol can't be resolved.
 (define jolt-chmod-755
-  (let ((c (guard (e (#t #f))
-             (load-shared-object #f)
-             (foreign-procedure "chmod" (string int) int))))
+  (let ((c (jolt-foreign-proc-safe "chmod" '(string int) 'int)))
     (lambda (path)
-      (if c
-          (c path #o755)
-          (system (string-append "chmod 755 '" path "'"))))))
+      (cond
+        (c (c path #o755))
+        ;; Windows has no chmod and needs none (execute is by extension)
+        ((let ((m (symbol->string (machine-type))))
+           (let loop ((i 0))
+             (cond ((> (+ i 2) (string-length m)) #f)
+                   ((string=? (substring m i (+ i 2)) "nt") #t)
+                   (else (loop (+ i 1))))))
+         0)
+        (else (system (string-append "chmod 755 '" path "'")))))))
 
 ;; A user-facing relative path resolves against JOLT_PWD — the user's cwd before
 ;; the launcher cd'd to the jolt repo root — matching the JVM, where io/file is
@@ -624,6 +629,31 @@
 ;; (Long. n) / (Long. "n"): a Long is just jolt's integer; return it (parse a string).
 (register-class-ctor! "Long" (lambda (x) (if (string? x) (parse-int-or-throw x 10 "Long") (->num (jnum->exact x)))))
 (register-class-ctor! "java.lang.Long" (lambda (x) (if (string? x) (parse-int-or-throw x 10 "Long") (->num (jnum->exact x)))))
+;; (Integer. n) / (Integer. "n"): jolt's integer, range-checked like intCast.
+(define (integer-ctor x)
+  (jolt-int-cast (if (string? x) (parse-int-or-throw x 10 "Integer") x)))
+(register-class-ctor! "Integer" integer-ctor)
+(register-class-ctor! "java.lang.Integer" integer-ctor)
+;; (Double. x) / (Double. "x"): jolt's double.
+(define (double-ctor x)
+  (if (string? x)
+      (let ((n (string->number x)))
+        (if n (exact->inexact n)
+            (jolt-throw (jolt-host-throwable "java.lang.NumberFormatException"
+                                             (string-append "For input string: \"" x "\"")))))
+      (jolt-double x)))
+(register-class-ctor! "Double" double-ctor)
+(register-class-ctor! "java.lang.Double" double-ctor)
+
+;; (Boolean. "true") / (Boolean. b): true for the string "true" (case-insensitive,
+;; anything else false) or the boolean itself — Boolean.valueOf semantics; the
+;; box is jolt's plain boolean.
+(define (boolean-ctor x)
+  (cond ((string? x) (string-ci=? x "true"))
+        ((boolean? x) x)
+        (else #f)))
+(register-class-ctor! "Boolean" boolean-ctor)
+(register-class-ctor! "java.lang.Boolean" boolean-ctor)
 
 ;; --- java.net.URI -----------------------------------------------------------
 ;; A minimal RFC-3986 split into scheme/authority/host/port/path/query/fragment,

host/chez/java/natives-array.ss

@@ -85,10 +85,8 @@
 (define (na-bytes x) (if (and (jolt-array? x) (eq? (jolt-array-kind x) 'byte)) x (na-byte-array x)))
 (define (na-bytes? x) (and (jolt-array? x) (eq? (jolt-array-kind x) 'byte)))
 (define (na-identity x) x)
-(define (na-byte x)
-  (let ((b (bitwise-and (exact (floor x)) #xff))) (if (>= b 128) (- b 256) b)))
-(define (na-short x)
-  (let ((s (bitwise-and (exact (floor x)) #xffff))) (if (>= s #x8000) (- s #x10000) s)))
+(define (na-byte x) (jolt-byte-cast x))
+(define (na-short x) (jolt-short-cast x))
 
 ;; --- chunked seqs -----------------------------------------------------------
 ;; The chunked-seq accessors (chunked-seq? / chunk-first / chunk-rest / chunk-next)
@@ -117,10 +115,11 @@
                  (let ((v (jolt-array-vec c)) (j (exact (na-idx i))))
                    (if (and (>= j 0) (< j (vector-length v))) (vector-ref v j) d))
                  (%na-nth c i d)))))
+(def-var! "jolt.host" "array-value?" (lambda (x) (if (jolt-array? x) #t jolt-nil)))
 (define %na-get jolt-get)
 (set! jolt-get
   (case-lambda
-    ((c k)   (if (jolt-array? c) (jolt-nth c k) (%na-get c k)))
+    ((c k)   (if (jolt-array? c) (jolt-nth c k jolt-nil) (%na-get c k)))
     ((c k d) (if (jolt-array? c) (jolt-nth c k d) (%na-get c k d)))))
 ;; aset (overlay) writes through jolt.host/ref-put! — mutate the slot, return arr.
 ;; count/nth/seq/get above are NATIVE-OPS (inlined at call sites), so aget/alength/

host/chez/joltc-selfbuild-smoke.sh

@@ -42,6 +42,20 @@ if [ "$got_e" != "45" ]; then
   exit 1
 fi
 
+# 2b. JOLT_TRACE must take effect in the BUILT binary. The env check runs at
+# runtime (the launcher), NOT at heap-build where JOLT_TRACE is always unset — so
+# an uncaught error shows a tail-frame trace recovering the TCO-elided chain, and
+# exactly ONE trace block (the launcher must not double-print it).
+got_tr="$(env -i HOME="$HOME" JOLT_TRACE=1 "$joltc" -e '(defn a [x] (+ x 1)) (defn b [x] (a x)) (b :x)' 2>&1)"
+if ! printf '%s' "$got_tr" | grep -q '  trace:' || ! printf '%s' "$got_tr" | grep -q 'b'; then
+  echo "  FAIL: JOLT_TRACE=1 in the built joltc produced no tail-frame trace"
+  echo "--- got ---"; echo "$got_tr"; exit 1
+fi
+if [ "$(printf '%s' "$got_tr" | grep -c '  trace:')" != "1" ]; then
+  echo "  FAIL: built joltc double-printed the trace block"
+  echo "--- got ---"; echo "$got_tr"; exit 1
+fi
+
 # 3. Build an app through the distributed joltc with an EMPTY environment — no
 # PATH at all, so no chez, no cc, no shell tools are reachable. This is the core
 # guarantee: joltc compiles apps entirely on its own.

host/chez/loader.ss

@@ -384,3 +384,14 @@
 (def-var! "jolt.host" "load-namespace" (lambda (n) (load-namespace n) jolt-nil))
 (def-var! "jolt.host" "file-exists?" (lambda (p) (if (file-exists? p) #t #f)))
 (def-var! "jolt.host" "getenv" (lambda (n) (let ((v (getenv n))) (if v v jolt-nil))))
+
+;; jolt version string. A self-contained binary build bakes the real tag into the
+;; saved heap by emitting (set! jolt-baked-version "…") in flat.ss; a dev run off
+;; the seed leaves it #f and falls back to $JOLT_VERSION (bin/joltc sets it from
+;; `git describe`), then "dev".
+(define jolt-baked-version #f)
+(def-var! "jolt.host" "jolt-version"
+  (lambda ()
+    (or jolt-baked-version
+        (let ((v (getenv "JOLT_VERSION"))) (and v (> (string-length v) 0) v))
+        "dev")))

host/chez/multimethods.ss

@@ -61,26 +61,36 @@
 
 (define (jolt-defmulti-setup name-sym dispatch . opts)
   (let-values (((dk h) (parse-mm-opts opts)))
-    (let ((mf (make-jolt-multifn (symbol-t-name name-sym) dispatch
-                                 (new-mm-table) dk h (new-mm-table))))
-      (def-var! (chez-current-ns) (symbol-t-name name-sym) mf)
+    (let* ((sns (symbol-t-ns name-sym))
+           ;; the macro qualifies the name with its EXPANSION ns, so a defmulti
+           ;; deferred inside a fn (a deftest body) still defines in the ns it
+           ;; was written in, not whatever ns is current when it finally runs.
+           (ns (if (string? sns) sns (chez-current-ns)))
+           (mf (make-jolt-multifn (symbol-t-name name-sym) dispatch
+                                  (new-mm-table) dk h (new-mm-table))))
+      (def-var! ns (symbol-t-name name-sym) mf)
       mf)))
 
 ;; (defmethod-setup 'mm dispatch-val impl) — add a method. Auto-creates the multifn
 ;; if absent (defmethod before defmulti — rare; identity dispatch as a fallback).
-(define (jolt-defmethod-setup mm-sym dval impl)
+(define (jolt-defmethod-setup mm-sym dval impl . rest)
   (let* ((nm (symbol-t-name mm-sym))
          (sns (symbol-t-ns mm-sym))
          (qns (and sns (not (jolt-nil? sns)) (not (null? sns)) sns))
+         ;; the macro passes its EXPANSION ns so a defmethod deferred inside a
+         ;; fn resolves like the JVM (against the ns it was written in, not the
+         ;; ns current when it runs); absent (old emitted code) fall back to the
+         ;; runtime ns.
+         (here (if (and (pair? rest) (string? (car rest))) (car rest) (chez-current-ns)))
          ;; qualified (cf.mm/ext) resolves in its own ns (cross-ns defmethod);
-         ;; unqualified resolves in the current ns, else a :refer's home ns (so a
+         ;; unqualified resolves in the writing ns, else a :refer's home ns (so a
          ;; defmethod on a referred multifn lands on the real one), else stays in
-         ;; the current ns (a shadow, as before).
+         ;; the writing ns (a shadow, as before).
          (mns (cond
-                (qns (or (chez-resolve-alias (chez-current-ns) qns) qns))
-                ((var-cell-lookup (chez-current-ns) nm) (chez-current-ns))
-                ((chez-resolve-refer (chez-current-ns) nm) => values)
-                (else (chez-current-ns))))
+                (qns (or (chez-resolve-alias here qns) qns))
+                ((var-cell-lookup here nm) here)
+                ((chez-resolve-refer here nm) => values)
+                (else here)))
          (cur (var-deref mns nm))
          (mf (if (jolt-multifn? cur) cur
                  ;; auto-create: copy the dispatch fn + default from a same-named

host/chez/natives-meta.ss

@@ -27,9 +27,9 @@
     ;; so dispatch to its meta method rather than the identity side-table — which
     ;; the deftype's reconstructed instances would not share.
     ((and (jrec? x) (jrec-cl x "meta")) => (lambda (m) (jolt-invoke m x)))
-    ((or (pvec? x) (pmap? x) (pset? x) (cseq? x) (empty-list-t? x) (jolt-lazyseq? x) (jrec? x) (jreify? x) (procedure? x))
-     (hashtable-ref meta-table x jolt-nil))
-    (else jolt-nil)))
+    ;; everything else (collections, fns, reify, atoms/agents and any reference
+    ;; type) reads the identity side-table; a value with no entry is nil meta.
+    (else (hashtable-ref meta-table x jolt-nil))))
 
 ;; fresh-identity copy of a metadatable value (so attaching meta doesn't mutate
 ;; the original). cseq/procedure can't be copied meaningfully — keyed in place.

host/chez/ns.ss

@@ -260,6 +260,9 @@
 ;; intern: create/set a var ns/sym to val (or an unbound cell). Returns the var.
 (define (jolt-intern ns-desig sym . vopt)
   (let ((nm (ns-desig->name ns-desig)) (s (symbol-t-name sym)))
+    ;; the namespace must exist (Namespace.find), like the JVM's intern
+    (unless (hashtable-ref ns-registry nm #f)
+      (jolt-throw (jolt-ex-info (string-append "No namespace: " nm " found") empty-pmap)))
     (if (pair? vopt) (def-var! nm s (car vopt)) (declare-var! nm s))))
 
 ;; alias / ns-unalias: register/drop an :as alias under the current (or given) ns.
@@ -306,13 +309,24 @@
         (loop (cddr a)))))
   jolt-nil)
 
-;; alter-meta! / reset-meta!: update a var's metadata (var-meta-table, rt.ss).
+;; alter-meta! / reset-meta!: a var's metadata lives in var-meta-table (rt.ss);
+;; any other reference (atom/agent/namespace) uses the identity meta side-table
+;; jolt-meta reads.
 (define (jolt-alter-meta! ref f . args)
-  (let* ((cur (or (hashtable-ref var-meta-table ref #f) (jolt-hash-map)))
-         (new (apply jolt-invoke f cur args)))
-    (hashtable-set! var-meta-table ref new)
-    new))
-(define (jolt-reset-meta! ref m) (hashtable-set! var-meta-table ref m) m)
+  (if (var-cell? ref)
+      (let* ((cur (or (hashtable-ref var-meta-table ref #f) (jolt-hash-map)))
+             (new (apply jolt-invoke f cur args)))
+        (hashtable-set! var-meta-table ref new)
+        new)
+      (let* ((cur (let ((m (jolt-meta ref))) (if (jolt-nil? m) (jolt-hash-map) m)))
+             (new (apply jolt-invoke f cur args)))
+        (hashtable-set! meta-table ref new)
+        new)))
+(define (jolt-reset-meta! ref m)
+  (if (var-cell? ref)
+      (hashtable-set! var-meta-table ref m)
+      (hashtable-set! meta-table ref m))
+  m)
 
 ;; --- RESOLVE FRICTION: native-op cells -------------------------------------
 ;; Native-op primitives (+ map reduce …) are INLINED at emit, so they have no

host/chez/post-prelude.ss

@@ -67,8 +67,13 @@
         ;; chain is a cseq under jolt's seq model, and (realized? (rest s)) after
         ;; a next must be true like the JVM's realized LazySeq — never a throw
         ;; whose message renders the (possibly infinite) seq.
-        ((cseq? x) (if (cseq-forced? x) #t #f))
-        ((empty-list-t? x) #t)
+        ;; a PLAIN seq (list/cons/range — not a lazy-seq wrapper) is not an
+        ;; IPending on the JVM: realized? throws.
+        ((or (cseq? x) (empty-list-t? x))
+         (jolt-throw (jolt-host-throwable
+                      "java.lang.ClassCastException"
+                      (string-append "class " (guard (e (#t "?")) (jolt-class-name x))
+                                     " cannot be cast to class clojure.lang.IPending"))))
         (else (jolt-invoke overlay-realized? x))))))
 ;; clojure.edn/read over a reader: drain the jhost reader, then read through the
 ;; overlay read-string so the opts map (:readers/:default/:eof) is honored.

host/chez/reader.ss

@@ -48,12 +48,24 @@
 
 (define (rdr-digit? c) (and (char>=? c #\0) (char<=? c #\9)))
 (define (rdr-octal? c) (and (char>=? c #\0) (char<=? c #\7)))
+(define (rdr-all-digits? s from to)
+  (and (> to from)
+       (let loop ((i from))
+         (cond ((>= i to) #t)
+               ((rdr-digit? (string-ref s i)) (loop (+ i 1)))
+               (else #f)))))
 ;; every char of s in [from,to) is an octal digit (and the span is non-empty).
 (define (rdr-all-octal? s from to)
   (and (fx<? from to)
        (let loop ((i from)) (cond ((fx=? i to) #t) ((rdr-octal? (string-ref s i)) (loop (fx+ i 1))) (else #f)))))
 
 ;; Advance past whitespace, commas, and ;-to-end-of-line comments.
+;; EDN strict mode (clojure.edn): auto-resolved keywords are invalid, and each
+;; discarded (#_) form is handed to rdr-discard-cb so the edn layer validates
+;; its tagged elements through :readers/:default like the JVM.
+(define rdr-edn-mode (make-parameter #f))
+(define rdr-discard-cb (make-parameter #f))
+
 (define (rdr-skip-ws s i end)
   (let loop ((i i))
     (cond
@@ -61,7 +73,8 @@
       ((rdr-ws? (string-ref s i)) (loop (+ i 1)))
       ((char=? (string-ref s i) #\;)
        (let eol ((j (+ i 1)))
-         (if (or (>= j end) (char=? (string-ref s j) #\newline))
+         (if (or (>= j end) (char=? (string-ref s j) #\newline)
+                 (char=? (string-ref s j) #\return))
              (loop j)
              (eol (+ j 1)))))
       (else i))))
@@ -115,12 +128,17 @@
          (slash (rdr-string-index-char body #\/)))
     (cond
       ;; ratio a/b -> exact rational (= JVM Ratio); reduces to an exact integer
-      ;; when d divides n.
+      ;; when d divides n. Both parts must be plain digit runs (1/-1 is an
+      ;; invalid token); a zero denominator is the JVM's divide error.
       (slash
-       (let ((n (string->number (substring body 0 slash)))
-             (d (string->number (substring body (+ slash 1) blen))))
-         (and (integer? n) (integer? d) (not (= d 0))
-              (* sign (/ n d)))))
+       (let ((ns (substring body 0 slash))
+             (ds (substring body (+ slash 1) blen)))
+         (and (rdr-all-digits? ns 0 (string-length ns))
+              (rdr-all-digits? ds 0 (string-length ds))
+              (let ((n (string->number ns)) (d (string->number ds)))
+                (when (= d 0)
+                  (jolt-throw (jolt-host-throwable "java.lang.ArithmeticException" "Divide by zero")))
+                (* sign (/ n d))))))
       ;; hex 0x..
       ((and (>= blen 2) (char=? (string-ref body 0) #\0)
             (or (char=? (string-ref body 1) #\x) (char=? (string-ref body 1) #\X)))
@@ -139,6 +157,11 @@
       ;; elsewhere or fall through (a non-octal digit fails rdr-all-octal?).
       ((and (>= blen 2) (char=? (string-ref body 0) #\0) (rdr-all-octal? body 1 blen))
        (let ((o (rdr-parse-radix (substring body 1 blen) 8))) (and o (* sign o))))
+      ;; a leading zero on a plain multi-digit integer is invalid (the octal
+      ;; branch above accepted real octals; 08/09 match the JVM's trailing
+      ;; "invalid number" alternative)
+      ((and (>= blen 2) (char=? (string-ref body 0) #\0) (rdr-all-digits? body 1 blen))
+       #f)
       ;; bigint suffix N
       ((and (> blen 1) (char=? (string-ref body (- blen 1)) #\N))
        (let ((n (string->number (substring body 0 (- blen 1)))))
@@ -190,7 +213,10 @@
               (let oct ((j (+ i 1)) (val 0) (cnt 0))
                 (if (and (fx<? cnt 3) (fx<? j end) (rdr-octal? (string-ref s j)))
                     (oct (fx+ j 1) (fx+ (fx* val 8) (fx- (char->integer (string-ref s j)) 48)) (fx+ cnt 1))
-                    (loop j (cons (integer->char val) acc)))))
+                    (begin
+                      (when (> val 255)
+                        (jolt-throw (jolt-ex-info "Octal escape sequence must be in range [0, 377]" empty-pmap)))
+                      (loop j (cons (integer->char val) acc))))))
              ((#\u)
               (let-values (((cp j) (rdr-hex->int s (+ i 2) 4)))
                 ;; A \u escape is a UTF-16 code unit. jolt chars are Unicode scalars,
@@ -208,7 +234,8 @@
                          (loop j (cons #\xFFFD acc)))))
                   ((and (fx>=? cp #xD800) (fx<=? cp #xDFFF)) (loop j (cons #\xFFFD acc)))
                   (else (loop j (cons (integer->char cp) acc))))))
-             (else (loop (+ i 2) (cons e acc))))))
+             (else (jolt-throw (jolt-ex-info (string-append "Unsupported escape character: \\" (string e))
+                                             empty-pmap))))))
         (else (loop (+ i 1) (cons c acc)))))))
 
 ;; backslash already consumed; read a Clojure character literal.
@@ -240,7 +267,10 @@
     ((char=? (string-ref name 0) #\u)
      (integer->char (string->number (substring name 1 (string-length name)) 16)))
     ((char=? (string-ref name 0) #\o)
-     (integer->char (string->number (substring name 1 (string-length name)) 8)))
+     (let ((v (string->number (substring name 1 (string-length name)) 8)))
+       (when (or (not v) (> v 255))
+         (jolt-throw (jolt-ex-info "Octal escape sequence must be in range [0, 377]" empty-pmap)))
+       (integer->char v)))
     (else (jolt-throw (jolt-ex-info (string-append "Unsupported character: \\" name)
                                     empty-pmap)))))
 
@@ -258,14 +288,39 @@
         (values #f tok)
         (values (substring tok 0 slash) (substring tok (+ slash 1) (string-length tok))))))
 
+(define (rdr-numeric-lead? tok)
+  (let ((len (string-length tok)))
+    (and (> len 0)
+         (let ((c0 (string-ref tok 0)))
+           (or (rdr-digit? c0)
+               (and (or (char=? c0 #\+) (char=? c0 #\-)) (> len 1)
+                    (rdr-digit? (string-ref tok 1))))))))
+(define (rdr-invalid-token tok)
+  (jolt-throw (jolt-host-throwable "java.lang.RuntimeException"
+                                   (string-append "Invalid token: " tok))))
 (define (rdr-token->value tok)
   (let ((n (rdr-try-number tok)))
     (cond
       (n n)
+      ;; a token that starts like a number but doesn't parse as one is an
+      ;; invalid number (1a, 08, 0x2g, 2r2), never a symbol — like the JVM.
+      ((rdr-numeric-lead? tok)
+       (jolt-throw (jolt-host-throwable "java.lang.NumberFormatException"
+                                        (string-append "Invalid number: " tok))))
       ((string=? tok "nil") jolt-nil)
       ((string=? tok "true") #t)
       ((string=? tok "false") #f)
-      (else (let-values (((ns name) (rdr-sym-parts tok))) (jolt-symbol ns name))))))
+      (else
+       (let ((len (string-length tok)))
+         ;; a lone "/" is the division symbol, and "ns//" names it in a
+         ;; namespace (clojure.core//); otherwise a leading or trailing slash
+         ;; leaves an empty ns/name part — an invalid token.
+         (when (and (> len 1)
+                    (or (char=? (string-ref tok 0) #\/)
+                        (and (char=? (string-ref tok (- len 1)) #\/)
+                             (not (and (> len 2) (char=? (string-ref tok (- len 2)) #\/))))))
+           (rdr-invalid-token tok))
+         (let-values (((ns name) (rdr-sym-parts tok))) (jolt-symbol ns name)))))))
 
 ;; --- collections ------------------------------------------------------------
 ;; Read forms until the close delimiter; returns (values reversed?-no list j).
@@ -289,6 +344,14 @@
 ;; sequence in a weak side-table the host contract's form-map-pairs consults.
 (define rdr-map-order (make-weak-eq-hashtable))
 (define (rdr-make-map es)
+  ;; the JVM reader rejects duplicate literal keys before building the map
+  (let dupchk ((kvs es) (seen empty-pset))
+    (when (pair? kvs)
+      (let ((k (car kvs)))
+        (when (jolt-truthy? (jolt-contains? seen k))
+          (jolt-throw (jolt-host-throwable "java.lang.IllegalArgumentException"
+                                           (string-append "Duplicate key: " (jolt-pr-str k)))))
+        (dupchk (cddr kvs) (pset-conj seen k)))))
   (let ((m (apply jolt-hash-map es)))
     (when (pair? es) (hashtable-set! rdr-map-order m es))
     m))
@@ -548,8 +611,12 @@
        (let-values (((src j) (rdr-read-regex s (+ i 1) end)))
          (values (jolt-re-pattern src) j)))
       ((char=? c #\_)                    ; #_ discard the next form
-       (let-values (((_ j) (rdr-read-form s (+ i 1) end)))
-         (when (rdr-eof? _) (jolt-throw (jolt-ex-info "EOF after #_" empty-pmap)))
+       (let-values (((d j) (rdr-read-form s (+ i 1) end)))
+         (when (rdr-eof? d) (jolt-throw (jolt-ex-info "EOF after #_" empty-pmap)))
+         ;; edn validates the discarded element (its tags go through the same
+         ;; :readers/:default pipeline; an unreadable one throws)
+         (let ((cb (rdr-discard-cb)))
+           (when cb (jolt-invoke cb d)))
          (rdr-read-form s j end)))
       ((char=? c #\')                    ; #'x var-quote -> (var x)
        (let-values (((form j) (rdr-read-form s (+ i 1) end)))
@@ -601,6 +668,17 @@
   (let ((auto? (and (< i end) (char=? (string-ref s i) #\:))))
     (let ((i (if auto? (+ i 1) i)))
       (let-values (((tok j) (rdr-read-token s i end)))
+        (let ((len (string-length tok)))
+          ;; ":" and "::" alone, a leading or trailing slash (a name of exactly
+          ;; "/" is fine, :ns//), or an auto-resolved keyword in edn (no
+          ;; resolution context) are invalid tokens.
+          (when (or (= len 0)
+                    (and (> len 1) (char=? (string-ref tok 0) #\/))
+                    (and (> len 1) (char=? (string-ref tok (- len 1)) #\/)
+                         (not (and (> len 2) (char=? (string-ref tok (- len 2)) #\/)))))
+            (rdr-invalid-token (string-append (if auto? "::" ":") tok)))
+          (when (and auto? (rdr-edn-mode))
+            (rdr-invalid-token (string-append "::" tok))))
         (let-values (((ns name) (rdr-sym-parts tok)))
           (if auto?
               (let* ((cur (chez-current-ns))
@@ -735,15 +813,76 @@
     (let ((v (var-deref "clojure.core" "*default-data-reader-fn*")))
       (and (not (jolt-nil? v)) (procedure? v) v))))
 
+;; strict #inst validation: RFC-3339 calendar fields must be real (month 1-12,
+;; day valid for the month incl. leap years, hour < 24, minute/second < 60).
+(define (rdr-2dig s i)
+  (and (< (+ i 1) (string-length s))
+       (rdr-digit? (string-ref s i)) (rdr-digit? (string-ref s (+ i 1)))
+       (+ (* 10 (- (char->integer (string-ref s i)) 48))
+          (- (char->integer (string-ref s (+ i 1))) 48))))
+(define (rdr-leap? y) (and (= 0 (modulo y 4)) (or (not (= 0 (modulo y 100))) (= 0 (modulo y 400)))))
+(define (rdr-inst-throw s)
+  (jolt-throw (jolt-host-throwable "java.lang.RuntimeException"
+                                   (string-append "Unrecognized date/time syntax: " s))))
+(define (rdr-validate-inst! s)
+  ;; progressive RFC-3339 like clojure.instant: yyyy[-MM[-dd[Thh[:mm[:ss[.f]]]]]]
+  ;; with an optional Z/±hh:mm offset; each present field must be in range
+  ;; (months 1-12, day valid for the month incl. leap years, hour < 24, min < 60).
+  (let* ((len (string-length s))
+         (y (and (>= len 4) (rdr-all-digits? s 0 4) (string->number (substring s 0 4)))))
+    (unless y (rdr-inst-throw s))
+    (when (>= len 5)
+      (unless (char=? (string-ref s 4) #\-) (rdr-inst-throw s))
+      (let ((mo (rdr-2dig s 5)))
+        (unless (and mo (>= mo 1) (<= mo 12)) (rdr-inst-throw s))
+        (when (>= len 8)
+          (unless (char=? (string-ref s 7) #\-) (rdr-inst-throw s))
+          (let ((d (rdr-2dig s 8)))
+            (unless (and d (>= d 1)
+                         (<= d (vector-ref (if (rdr-leap? y)
+                                               '#(31 29 31 30 31 30 31 31 30 31 30 31)
+                                               '#(31 28 31 30 31 30 31 31 30 31 30 31))
+                                           (- mo 1))))
+              (rdr-inst-throw s))
+            (when (>= len 11)
+              (unless (char=? (string-ref s 10) #\T) (rdr-inst-throw s))
+              (let ((h (rdr-2dig s 11)))
+                (unless (and h (<= h 23)) (rdr-inst-throw s))
+                (when (>= len 14)
+                  (when (char=? (string-ref s 13) #\:)
+                    (let ((mi (rdr-2dig s 14)))
+                      (unless (and mi (<= mi 59)) (rdr-inst-throw s)))))))))))))
+;; strict #uuid: canonical 8-4-4-4-12 hex groups.
+(define (rdr-validate-uuid! s)
+  (define (hexrun? from to)
+    (let loop ((i from))
+      (cond ((>= i to) #t)
+            ((let ((c (char-downcase (string-ref s i))))
+               (or (rdr-digit? c) (and (char>=? c #\a) (char<=? c #\f))))
+             (loop (+ i 1)))
+            (else #f))))
+  (unless (and (= (string-length s) 36)
+               (char=? (string-ref s 8) #\-) (char=? (string-ref s 13) #\-)
+               (char=? (string-ref s 18) #\-) (char=? (string-ref s 23) #\-)
+               (hexrun? 0 8) (hexrun? 9 13) (hexrun? 14 18) (hexrun? 19 23) (hexrun? 24 36))
+    (jolt-throw (jolt-host-throwable "java.lang.IllegalArgumentException"
+                                     (string-append "Invalid UUID string: " s)))))
+
 ;; read-string / read data seam: construct the value for a #tag literal. #inst,
 ;; #uuid and #"regex" are built in; any other tag is applied from *data-readers*,
 ;; then *default-data-reader-fn*. An unregistered tag with no default handler stays
 ;; a tagged FORM (lenient — clojure.edn raises instead).
 (define (rdr-construct-tag tag inner)
   (cond
-    ((eq? tag (keyword #f "#inst")) (jolt-inst-from-string inner))
-    ((eq? tag (keyword #f "#uuid")) (jolt-uuid-from-string inner))
+    ((eq? tag (keyword #f "#inst"))
+     (when (string? inner) (rdr-validate-inst! inner))
+     (jolt-inst-from-string inner))
+    ((eq? tag (keyword #f "#uuid"))
+     (when (string? inner) (rdr-validate-uuid! inner))
+     (jolt-uuid-from-string inner))
     ((eq? tag (keyword #f "regex")) (jolt-re-pattern inner))
+    ;; the M-literal form: construct the BigDecimal from its numeric text
+    ((eq? tag (keyword #f "bigdec")) (jolt-bigdec-from-string inner))
     (else (let ((fn (rdr-data-reader-fn tag)))
             (if fn (jolt-invoke fn inner)
                 (let ((dfn (rdr-default-data-reader-fn)))
@@ -765,7 +904,11 @@
      (let ((items (jolt-get x rdr-kw-value)))
        (let loop ((i 0) (s empty-pset))
          (if (fx>=? i (pvec-count items)) s
-             (loop (fx+ i 1) (pset-conj s (rdr-form->data (pvec-nth-d items i jolt-nil))))))))
+             (let ((v (rdr-form->data (pvec-nth-d items i jolt-nil))))
+               (when (jolt-truthy? (jolt-contains? s v))
+                 (jolt-throw (jolt-host-throwable "java.lang.IllegalArgumentException"
+                                                  (string-append "Duplicate key: " (jolt-pr-str v)))))
+               (loop (fx+ i 1) (pset-conj s v)))))))
     ((pvec? x)
      (let-values (((items changed) (rdr-conv-each (vector->list (pvec-v x)))))
        (if changed (apply jolt-vector items) x)))
@@ -790,12 +933,35 @@
     (if (jolt-nil? m) v (jolt-with-meta v (rdr-form->data m)))))
 
 ;; --- the two host seams -----------------------------------------------------
+;; a top-level read: a stray close delimiter is unmatched (read-seq consumes the
+;; close of an open collection; anything reaching here is unbalanced input).
+(define (rdr-read-top s i end)
+  (let ((k (rdr-skip-ws s i end)))
+    (when (and (< k end)
+               (let ((c (string-ref s k)))
+                 (or (char=? c #\)) (char=? c #\]) (char=? c #\}))))
+      (jolt-throw (jolt-ex-info (string-append "Unmatched delimiter: "
+                                               (string (string-ref s k)))
+                                empty-pmap)))
+    (rdr-read-form s k end)))
+
 ;; clojure.core/read-string: first form, or nil for blank / comment-only input
 ;; (parse-string wart, matched deliberately). jolt-read-form-raw keeps set FORMS
 ;; for the compiler spine (compile-eval); the data seam converts them to sets.
 (define (jolt-read-form-raw s)
-  (let-values (((form j) (rdr-read-form s 0 (string-length s))))
+  (let-values (((form j) (rdr-read-top s 0 (string-length s))))
     (if (rdr-eof? form) jolt-nil form)))
+
+;; the edn seam: strict mode (no auto-resolved keywords), each #_ discard handed
+;; to the callback for tag validation, and a distinct EOF sentinel so the edn
+;; layer can honor its :eof option (nil input is a plain EOF).
+(define (jolt-read-form-edn s cb)
+  (if (jolt-nil? s)
+      (keyword "jolt" "reader-eof")
+      (parameterize ((rdr-edn-mode #t)
+                     (rdr-discard-cb (if (jolt-nil? cb) #f cb)))
+        (let-values (((form j) (rdr-read-top s 0 (string-length s))))
+          (if (rdr-eof? form) (keyword "jolt" "reader-eof") form)))))
 (define (jolt-read-string s)
   (let ((form (jolt-read-form-raw s)))
     (if (jolt-nil? form) form (rdr-form->data form))))
@@ -803,7 +969,7 @@
 ;; __parse-next: [form rest-of-string] or nil when only whitespace/comments left.
 (define (jolt-parse-next s)
   (let ((end (string-length s)))
-    (let-values (((form j) (rdr-read-form s 0 end)))
+    (let-values (((form j) (rdr-read-top s 0 end)))
       (if (rdr-eof? form)
           jolt-nil
           (jolt-vector (rdr-form->data form) (substring s j end))))))
@@ -812,8 +978,13 @@
 ;; is the :#name keyword the reader produced; #uuid/#inst reuse the inst-time ctors.
 (define (jolt-read-tagged tag form)
   (cond
-    ((eq? tag (keyword #f "#uuid")) (jolt-uuid-from-string form))
-    ((eq? tag (keyword #f "#inst")) (jolt-inst-from-string form))
+    ((eq? tag (keyword #f "#uuid"))
+     (when (string? form) (rdr-validate-uuid! form))
+     (jolt-uuid-from-string form))
+    ((eq? tag (keyword #f "#inst"))
+     (when (string? form) (rdr-validate-inst! form))
+     (jolt-inst-from-string form))
+    ((eq? tag (keyword #f "bigdec")) (jolt-bigdec-from-string form))
     ;; No registered reader: consult *default-data-reader-fn*, else throw a clean,
     ;; catchable ex-info naming the tag, like the JVM's "No reader function for tag
     ;; foobar" (empty-pmap is a VALUE — the old (empty-pmap) applied it as a
@@ -833,3 +1004,4 @@
 ;; :default (a #inst can be overridden to defer), rather than read-string building
 ;; the built-in #inst eagerly (which fails on a non-string like #inst ^:ref […]).
 (def-var! "clojure.core" "__read-form-raw" jolt-read-form-raw)
+(def-var! "clojure.core" "__read-form-edn" jolt-read-form-edn)

host/chez/records.ss

@@ -44,6 +44,10 @@
 ;; resolves "Raw" to its real tag "a.util.Raw" here instead of prepending the
 ;; calling ns. The local ns is preferred, so a same-named local type still wins.
 (define chez-deftype-tag-set (make-hashtable string-hash string=?))
+;; ctor procedure -> its class tag: the type NAME var holds the ctor (a jolt-ism;
+;; the JVM resolves it to the class), so class-key maps the ctor back to the
+;; class for (ancestors TypeName) / (isa? x TypeName) / derive on the type.
+(define chez-deftype-ctor-tag (make-weak-eq-hashtable))
 (define chez-simple-name-tag (make-hashtable string-hash string=?))
 ;; a jrec that is coll? — a record, or a deftype implementing a collection
 ;; interface (its seq/count/nth/valAt/cons method is registered). find-method-any-
@@ -618,6 +622,11 @@
     ;; index the tag so a cross-ns extend-protocol resolves the bare type name.
     (hashtable-set! chez-deftype-tag-set tag #t)
     (hashtable-set! chez-simple-name-tag (symbol-t-name name-sym) tag)
+    ;; graft the type onto the class graph so isa?/supers/ancestors see it. A
+    ;; bare deftype is an IType; defrecord (which runs register-record-type!
+    ;; right after) replaces the row with the record interface set.
+    (jch-set-supers! tag '("clojure.lang.IType"))
+    (hashtable-set! chez-deftype-ctor-tag ctor tag)
     ;; record the shape for whole-program inference, keyed by the positional
     ;; ctor var "ns/->Name" the analyzer resolves a (->Name …) call to.
     (register-record-shape! (string-append (chez-current-ns) "/->" (symbol-t-name name-sym))
@@ -689,9 +698,14 @@
                   type-name)))
     ;; a host class if the literal set lists it OR the class graph models it — both
     ;; feed value-host-tags (which emits the same bare segment), so a protocol
-    ;; extended to any modeled class keys under a tag the value reports.
+    ;; extended to any modeled class keys under a tag the value reports. A
+    ;; deftype/defrecord is in the graph too (its ancestry), but its VALUES report
+    ;; the ns-qualified tag, not the bare segment — so a name that resolves to a
+    ;; deftype never canonicalizes through the graph arm.
     (and (or (hashtable-ref host-type-set base #f)
-             (jch-known? base) (jch-known? type-name))
+             (and (not (hashtable-ref chez-simple-name-tag type-name #f))
+                  (not (hashtable-ref chez-deftype-tag-set type-name #f))
+                  (or (jch-known? base) (jch-known? type-name))))
          base)))
 ;; An extend/extend-type/extend-protocol registration marks the tag as an
 ;; extender of the protocol (recorded inside type-registry so the per-case prune
@@ -731,6 +745,12 @@
                  (let ((h (make-hashtable string-hash string=?))) (hashtable-set! type-registry tag h) h))))
     (unless (hashtable-ref ti proto-name #f)
       (hashtable-set! ti proto-name (make-hashtable string-hash string=?))))
+  ;; the protocol's interface joins the type's class ancestry, spelled like the
+  ;; JVM interface (munged ns; the defining ns is assumed to be the current one —
+  ;; the macro passes only the simple protocol name).
+  (let ((iface (string-append (jch-munge-segments (chez-current-ns)) "." proto-name)))
+    (jch-mark-interface! iface)
+    (jch-register-supers! (string-append (chez-current-ns) "." type-name) (list iface)))
   jolt-nil)
 
 ;; protocol-resolve: the impl procedure for obj — by record type tag, a reify's
@@ -1050,8 +1070,18 @@
 ;; defrecord marks its type a record (deftype does not), keyed by the same
 ;; "ns.Name" tag make-deftype-ctor bakes — so jrec-record? distinguishes the two.
 (define (register-record-type! name-sym)
-  (hashtable-set! chez-record-type-tbl
-                  (string-append (chez-current-ns) "." (symbol-t-name name-sym)) #t)
+  (let ((tag (string-append (chez-current-ns) "." (symbol-t-name name-sym))))
+    (hashtable-set! chez-record-type-tbl tag #t)
+    ;; a defrecord's class ancestry: replace the deftype IType row with the
+    ;; record interfaces (their closure supplies Associative/Seqable/ILookup/…),
+    ;; keeping any protocol interfaces already grafted by the inline
+    ;; registrations that ran between the deftype ctor and this call.
+    (let ((protos (filter (lambda (s) (not (string=? s "clojure.lang.IType")))
+                          (jch-direct-supers tag))))
+      (jch-set-supers! tag (append protos
+                                   '("clojure.lang.IRecord" "clojure.lang.IObj"
+                                     "clojure.lang.IPersistentMap" "java.util.Map"
+                                     "clojure.lang.IHashEq" "java.io.Serializable")))))
   jolt-nil)
 (def-var! "clojure.core" "register-record-type!" register-record-type!)
 (def-var! "clojure.core" "make-protocol" make-protocol)

host/chez/rt.ss

@@ -11,6 +11,17 @@
 ;; Emitted programs do `(load "host/chez/rt.ss")`; this loads values.ss in turn.
 
 (load "host/chez/values.ss")
+;; Resolve a libc entry point at RUN time. A literal (foreign-procedure "name" …)
+;; in COMPILED code becomes a fasl relocation resolved when the boot loads — on a
+;; platform lacking the symbol (chmod/sigaddset on Windows) that kills the boot
+;; before any guard can run. eval defers the lookup to evaluation time, where the
+;; guard works; returns #f when the entry doesn't exist.
+(define (jolt-foreign-proc-safe name args res)
+  (guard (e (#t #f))
+    (load-shared-object #f)
+    (and (foreign-entry? name)
+         (eval `(foreign-procedure ,name ,args ,res)))))
+
 (load "host/chez/collections.ss")
 (load "host/chez/seq.ss")
 
@@ -49,6 +60,112 @@
 ;; stack trace (source-registry.ss). call/cc is paid only on a throw, never per
 ;; call; the captured k is walked, never invoked.
 (define jolt-throw-cont (make-thread-parameter #f))
+
+;; --- tail-frame history: a ring of rings (opt-in) ----------------------------
+;; TCO erases tail-called frames from the native continuation, so an uncaught
+;; error's backtrace shows only the surviving non-tail spine — the immediate error
+;; site is often a tail call and is missing. When tracing is enabled (JOLT_TRACE,
+;; wired in compile-eval.ss), each compiled fn records its frame-name on entry, and
+;; the reporter reads this history to recover TCO-elided frames.
+;;
+;; The store is MIT-Scheme's "history" shape — a ring of rings. The OUTER ring
+;; holds one RIB per non-tail subproblem (the real call spine); each rib's INNER
+;; ring holds the recent tail-calls made AT that subproblem. A non-tail entry
+;; advances the outer ring (a fresh rib); a tail entry rotates the current rib's
+;; inner ring. So a tight tail loop (mutual recursion, a non-recur self-tail-call)
+;; churns ONE rib's small inner ring instead of flushing the outer spine — the
+;; caller context that led into the loop survives. Both rings are fixed-size, so
+;; the whole history is bounded: a constant space factor, NOT a change to the
+;; asymptotic space TCO guarantees.
+;;
+;; Whether an entry is tail or non-tail is set by the CALLER: the emitter marks a
+;; tail call with (jolt-trace-mark! #t) right before it; a non-tail entry is the
+;; default. NOTE this is best-effort: a tail call routed through jolt-invoke to a
+;; target that has no entry prologue (a core/native fn, an anonymous fn held in a
+;; var) does not consume the mark, so a following non-tail frame can be mislabeled
+;; as a tail rotation — a cosmetic mis-grouping in the trace, never a wrong result.
+(define jolt-trace-outer-size 48)          ; ribs (non-tail spine depth kept)
+(define jolt-trace-inner-size 6)           ; tail-calls kept per subproblem
+;; A history: #(ribs-vector outer-head outer-count). A rib: #(name-vector head count).
+(define (jolt-make-rib) (vector (make-vector jolt-trace-inner-size #f) 0 0))
+(define (jolt-make-history)
+  (let ((ribs (make-vector jolt-trace-outer-size #f)))
+    (let loop ((i 0))
+      (when (fx<? i jolt-trace-outer-size)
+        (vector-set! ribs i (jolt-make-rib)) (loop (fx+ i 1))))
+    (vector ribs 0 0)))
+;; A global switch (all threads) plus a per-thread ring, lazily created on first
+;; use — so code run on a spawned thread (a future/agent) records into ITS OWN
+;; history, not the enabling thread's (make-thread-parameter hands a new thread the
+;; initial #f, so we can't rely on inheritance).
+(define jolt-trace-on? #f)
+(define jolt-trace-ring (make-thread-parameter #f))
+(define jolt-trace-tail? (make-thread-parameter #f))   ; caller-set, consumed per entry
+(define (jolt-trace-enable!) (set! jolt-trace-on? #t) (jolt-trace-ring (jolt-make-history)))
+;; this thread's ring, created on demand while tracing is on
+(define (jolt-trace-cur-ring)
+  (or (jolt-trace-ring)
+      (and jolt-trace-on? (let ((h (jolt-make-history))) (jolt-trace-ring h) h))))
+;; Drop accumulated history at a top-level boundary (compile-eval.ss calls this per
+;; top-level form) so an error's trace shows only the forms that led to it, not the
+;; frames of earlier, already-returned REPL/eval forms.
+(define (jolt-trace-reset!)
+  (when (jolt-trace-ring) (jolt-trace-ring (jolt-make-history)) (jolt-trace-tail? #f)))
+(define (jolt-trace-mark! t) (jolt-trace-tail? t))
+
+;; push name into a rib's inner ring
+(define (jolt-rib-push! rib name)
+  (let ((buf (vector-ref rib 0)) (i (vector-ref rib 1)) (cnt (vector-ref rib 2)))
+    (vector-set! buf i name)
+    (vector-set! rib 1 (fxmod (fx+ i 1) jolt-trace-inner-size))
+    (when (fx<? cnt jolt-trace-inner-size) (vector-set! rib 2 (fx+ cnt 1)))))
+;; a non-tail entry: advance the outer ring, reset the new rib, seed it with name
+(define (jolt-history-nontail! h name)
+  (let* ((ribs (vector-ref h 0)) (oh (vector-ref h 1)) (oc (vector-ref h 2))
+         (rib (vector-ref ribs oh)))
+    (vector-set! rib 1 0) (vector-set! rib 2 0)
+    (jolt-rib-push! rib name)
+    (vector-set! h 1 (fxmod (fx+ oh 1) jolt-trace-outer-size))
+    (when (fx<? oc jolt-trace-outer-size) (vector-set! h 2 (fx+ oc 1)))))
+;; a tail entry: rotate the CURRENT rib's inner ring (bootstrap a rib if none yet)
+(define (jolt-history-tail! h name)
+  (if (fx=? (vector-ref h 2) 0)
+      (jolt-history-nontail! h name)
+      (let* ((ribs (vector-ref h 0))
+             (cur (fxmod (fx+ (fx- (vector-ref h 1) 1) jolt-trace-outer-size)
+                         jolt-trace-outer-size)))
+        (jolt-rib-push! (vector-ref ribs cur) name))))
+;; Record a frame entry, routed by the caller's tail mark; then reset the mark so a
+;; subsequent entry reached WITHOUT a mark (e.g. via apply) defaults to non-tail.
+(define (jolt-trace-push! name)
+  (let ((h (jolt-trace-cur-ring)))
+    (when h
+      (if (jolt-trace-tail?) (jolt-history-tail! h name) (jolt-history-nontail! h name))
+      (jolt-trace-tail? #f)))
+  jolt-nil)
+
+;; a rib's inner names, most-recent (deepest) tail first
+(define (jolt-rib-names rib)
+  (let ((buf (vector-ref rib 0)) (head (vector-ref rib 1)) (cnt (vector-ref rib 2)))
+    (let loop ((k 1) (acc '()))
+      (if (fx>? k cnt)
+          (reverse acc)
+          (loop (fx+ k 1)
+                (cons (vector-ref buf (fxmod (fx+ (fx- head k) jolt-trace-inner-size)
+                                             jolt-trace-inner-size))
+                      acc))))))
+;; The whole history flattened to frame-names, most-recent (deepest) first:
+;; current rib's tail-history, then its non-tail caller's, and so on outward.
+(define (jolt-trace-snapshot)
+  (let ((h (jolt-trace-ring)))
+    (if (not h) '()
+        (let* ((ribs (vector-ref h 0)) (oh (vector-ref h 1)) (oc (vector-ref h 2)))
+          (let loop ((k 1) (acc '()))
+            (if (fx>? k oc)
+                (apply append (reverse acc))
+                (let ((idx (fxmod (fx+ (fx- oh k) jolt-trace-outer-size) jolt-trace-outer-size)))
+                  (loop (fx+ k 1) (cons (jolt-rib-names (vector-ref ribs idx)) acc)))))))))
+
 (define-condition-type &jolt-throw &condition
   make-jolt-throw-condition jolt-throw-condition?
   (value jolt-throw-condition-value))

host/chez/run-corpus.ss

@@ -11,7 +11,7 @@
 ;; reset between cases so there is no leakage — same isolation a fresh process gives.
 ;;
 ;;   chez --script host/chez/run-corpus.ss
-;;   JOLT_CHEZ_ZJ_FLOOR=N   override the regression floor (default 2730)
+;;   JOLT_CHEZ_ZJ_FLOOR=N   override the regression floor (default 3390)
 ;;   JOLT_CORPUS_LIMIT=N    every-Nth stride (fast iteration; floor drops to 0)
 ;;   JOLT_DUMP_CRASH_LABELS=1   list crash + allowlisted labels
 (import (chezscheme))
@@ -196,7 +196,7 @@
 
 ;; Regression floor: fail on any NEW divergence or if pass drops below the floor.
 (define base-floor (let ((s (getenv "JOLT_CHEZ_ZJ_FLOOR")))
-                     (if s (string->number s) 2730)))
+                     (if s (string->number s) 3390)))
 (define floor (if limit 0 base-floor))
 (when (or (> (length diverged) 0) (< pass floor))
   (printf "REGRESSION: pass ~a < floor ~a or ~a new divergence(s)\n"

host/chez/seq.ss

@@ -158,17 +158,218 @@
               ((fx=? i 0) (seq-first s))
               (else (loop (jolt-seq (seq-more s)) (fx- i 1)))))))
 
+;; --- checked arithmetic: JVM Numbers.ops-style category dispatch -------------
+;; Every arithmetic/comparison site (the inlined jolt-n* macros in call position,
+;; the variadic shims in value position) funnels a binary op through ONE dispatch:
+;; both operands inside Chez's tower take the native op with JVM contagion rules
+;; patched in (a double operand wins — Chez's exact-zero shortcut must not leak:
+;; (* 1.5 0) is 0.0, not 0; an exact zero divisor throws ArithmeticException, a
+;; double zero divisor yields ##Inf/##NaN); an operand OUTSIDE the tower (e.g.
+;; BigDecimal) falls to a slow hook the numeric shim extends (java/bigdec.ss).
+;; A non-numeric operand is a ClassCastException, like the JVM.
+(define (jolt-num-cast-throw x)
+  (if (jolt-nil? x)
+      (jolt-throw (jolt-host-throwable "java.lang.NullPointerException" ""))
+      (jolt-throw (jolt-host-throwable
+                   "java.lang.ClassCastException"
+                   (string-append "class " (jolt-class-name x)
+                                  " cannot be cast to class java.lang.Number")))))
+(define (jolt-div0-throw)
+  (jolt-throw (jolt-host-throwable "java.lang.ArithmeticException" "Divide by zero")))
+
+;; slow hooks: one per op, taking over when an operand is outside Chez's tower.
+;; A numeric shim (java/bigdec.ss) set!-extends them; the base case is the JVM's:
+;; not a number -> ClassCastException. The hooks are BINARY and never re-enter
+;; the variadic shims, so extension order can't recurse.
+(define (jolt-add-slow a b) (jolt-num-cast-throw (if (number? a) b a)))
+(define (jolt-sub-slow a b) (jolt-num-cast-throw (if (number? a) b a)))
+(define (jolt-mul-slow a b) (jolt-num-cast-throw (if (number? a) b a)))
+(define (jolt-div-slow a b) (jolt-num-cast-throw (if (number? a) b a)))
+;; comparison of operands outside the Chez tower: numeric shims extend this to a
+;; 3-way compare; anything left over is not a number.
+(define (jolt-num-cmp-slow a b)
+  (jolt-num-cast-throw (if (number? a) b a)))
+
+(define (jolt-add2 a b)
+  (if (and (number? a) (number? b)) (+ a b) (jolt-add-slow a b)))
+(define (jolt-sub2 a b)
+  (if (and (number? a) (number? b)) (- a b) (jolt-sub-slow a b)))
+(define (jolt-mul2 a b)
+  (if (and (number? a) (number? b))
+      (if (or (flonum? a) (flonum? b))
+          (fl* (real->flonum a) (real->flonum b))
+          (* a b))
+      (jolt-mul-slow a b)))
+(define (jolt-div2 a b)
+  (if (and (number? a) (number? b))
+      (if (or (flonum? a) (flonum? b))
+          (fl/ (real->flonum a) (real->flonum b))
+          (if (eqv? b 0) (jolt-div0-throw) (/ a b)))
+      (jolt-div-slow a b)))
+(define (jolt-lt2 a b)
+  (if (and (number? a) (number? b)) (< a b) (< (jolt-num-cmp-slow a b) 0)))
+(define (jolt-gt2 a b)
+  (if (and (number? a) (number? b)) (> a b) (> (jolt-num-cmp-slow a b) 0)))
+(define (jolt-le2 a b)
+  (if (and (number? a) (number? b)) (<= a b) (<= (jolt-num-cmp-slow a b) 0)))
+(define (jolt-ge2 a b)
+  (if (and (number? a) (number? b)) (>= a b) (>= (jolt-num-cmp-slow a b) 0)))
+;; min/max return the ORIGINAL operand (type and exactness kept, like
+;; Numbers.min): (min 1 2.0) is 1, not 1.0. A NaN operand wins.
+(define (jolt-min2 a b)
+  (cond ((and (flonum? a) (nan? a)) a)
+        ((and (flonum? b) (nan? b)) b)
+        (else (if (jolt-lt2 a b) a b))))
+(define (jolt-max2 a b)
+  (cond ((and (flonum? a) (nan? a)) a)
+        ((and (flonum? b) (nan? b)) b)
+        (else (if (jolt-gt2 a b) a b))))
+
+;; quot/rem/mod over the full tower: truncating division; a double operand makes
+;; the result a double; mod has floor semantics (result takes the divisor's
+;; sign). A zero divisor throws ArithmeticException in both worlds (JVM double
+;; quot/rem check the divisor before dividing). Non-tower operands hit the
+;; set!-extensible slow hooks.
+(define (jolt-quot-slow a b) (jolt-num-cast-throw (if (number? a) b a)))
+(define (jolt-rem-slow a b) (jolt-num-cast-throw (if (number? a) b a)))
+(define (jolt-mod-slow a b) (jolt-num-cast-throw (if (number? a) b a)))
+(define (jolt-quot a b)
+  (cond ((not (and (number? a) (number? b))) (jolt-quot-slow a b))
+        ((or (flonum? a) (flonum? b))
+         (let ((n (real->flonum a)) (d (real->flonum b)))
+           (if (fl= d 0.0) (jolt-div0-throw)
+               (let ((q (fl/ n d)))
+                 (when (or (nan? q) (infinite? q))
+                   (jolt-throw (jolt-host-throwable "java.lang.NumberFormatException"
+                                                    "Infinite or NaN")))
+                 (fltruncate q)))))
+        ((eqv? b 0) (jolt-div0-throw))
+        ((and (integer? a) (integer? b)) (quotient a b))
+        (else (truncate (/ a b)))))
+(define (jolt-rem a b)
+  (cond ((not (and (number? a) (number? b))) (jolt-rem-slow a b))
+        ((or (flonum? a) (flonum? b))
+         (let ((n (real->flonum a)) (d (real->flonum b)))
+           (if (fl= d 0.0) (jolt-div0-throw)
+               (let ((q (fl/ n d)))
+                 (when (or (nan? q) (infinite? q))
+                   (jolt-throw (jolt-host-throwable "java.lang.NumberFormatException"
+                                                    "Infinite or NaN")))
+                 (fl- n (fl* d (fltruncate q)))))))
+        ((eqv? b 0) (jolt-div0-throw))
+        ((and (integer? a) (integer? b)) (remainder a b))
+        (else (- a (* b (truncate (/ a b)))))))
+(define (jolt-mod a b)
+  (cond ((not (and (number? a) (number? b))) (jolt-mod-slow a b))
+        ((and (integer? a) (integer? b) (not (flonum? a)) (not (flonum? b)))
+         (if (eqv? b 0) (jolt-div0-throw) (modulo a b)))
+        (else
+         (let ((m (jolt-rem a b)))
+           (if (or (zero? m) (eq? (negative? m) (negative? b))) m (jolt-add2 m b))))))
+
 ;; value-position arithmetic (the higher-order forms: (reduce + []), (apply * xs)).
-;; Scheme's +/-/*// already implement the JVM-parity numeric tower: exact+exact ->
-;; exact, exact/exact -> Ratio, any flonum -> flonum. Identities (+)=0 / (*)=1 are
-;; exact, matching exact integer arithmetic. The hot path uses the inlined native
-;; ops, not these.
-(define (jolt-add . xs) (apply + xs))
-(define (jolt-sub . xs) (apply - xs))
-(define (jolt-mul . xs) (apply * xs))
-(define (jolt-div . xs) (apply / xs))
-(define (jolt-min . xs) (apply min xs))
-(define (jolt-max . xs) (apply max xs))
+;; Folded through the binary dispatch so contagion/edge rules hold; identities
+;; (+)=0 / (*)=1 are exact, matching exact integer arithmetic. The hot path uses
+;; the inlined native ops, not these.
+;; recognizer for slow-path numeric types; numeric shims extend it.
+(define (jolt-num-slow? x) #f)
+(define (jolt-num-check1 x)   ; (+ x)/(* x) return x but still type-check it
+  (if (or (number? x) (jolt-num-slow? x)) x (jolt-num-cast-throw x)))
+(define (jolt-add . xs)
+  (cond ((null? xs) 0)
+        ((null? (cdr xs)) (jolt-num-check1 (car xs)))
+        (else (fold-left jolt-add2 (car xs) (cdr xs)))))
+(define (jolt-arity0-throw name)
+  (jolt-throw (jolt-host-throwable
+               "clojure.lang.ArityException"
+               (string-append "Wrong number of args (0) passed to: clojure.core/" name))))
+(define (jolt-sub . xs)
+  (cond ((null? xs) (jolt-arity0-throw "-"))
+        ((null? (cdr xs)) (jolt-sub2 0 (car xs)))
+        (else (fold-left jolt-sub2 (car xs) (cdr xs)))))
+(define (jolt-mul . xs)
+  (cond ((null? xs) 1)
+        ((null? (cdr xs)) (jolt-num-check1 (car xs)))
+        (else (fold-left jolt-mul2 (car xs) (cdr xs)))))
+(define (jolt-div . xs)
+  (cond ((null? xs) (jolt-arity0-throw "/"))
+        ((null? (cdr xs)) (jolt-div2 1 (car xs)))
+        (else (fold-left jolt-div2 (car xs) (cdr xs)))))
+(define (jolt-min x . xs) (fold-left jolt-min2 x xs))
+(define (jolt-max x . xs) (fold-left jolt-max2 x xs))
+;; variadic comparison chains for value position ((apply < xs)).
+(define (jolt-cmp-chain op2)
+  (lambda (x . xs)
+    (let loop ((a x) (rest xs))
+      (cond ((null? rest) #t)
+            ((op2 a (car rest)) (loop (car rest) (cdr rest)))
+            (else #f)))))
+(define jolt-lt (jolt-cmp-chain jolt-lt2))
+(define jolt-gt (jolt-cmp-chain jolt-gt2))
+(define jolt-le (jolt-cmp-chain jolt-le2))
+(define jolt-ge (jolt-cmp-chain jolt-ge2))
+
+;; call-position arithmetic: inlined macros with the both-Chez-numbers fast path
+;; open-coded; anything else falls to the binary dispatch above. Comparisons
+;; return a genuine Scheme boolean (the backend's truthy elision relies on it).
+(define-syntax jolt-n+
+  (syntax-rules ()
+    ((_) 0)
+    ((_ a) (jolt-add a))
+    ((_ ea eb) (let ((a ea) (b eb))
+                 (if (and (number? a) (number? b)) (+ a b) (jolt-add a b))))
+    ((_ a b c ...) (jolt-n+ (jolt-n+ a b) c ...))))
+(define-syntax jolt-n-
+  (syntax-rules ()
+    ((_) (jolt-sub))
+    ((_ a) (jolt-sub a))
+    ((_ ea eb) (let ((a ea) (b eb))
+                 (if (and (number? a) (number? b)) (- a b) (jolt-sub a b))))
+    ((_ a b c ...) (jolt-n- (jolt-n- a b) c ...))))
+(define-syntax jolt-n*
+  (syntax-rules ()
+    ((_) 1)
+    ((_ a) (jolt-mul a))
+    ((_ ea eb) (let ((a ea) (b eb))
+                 (if (and (number? a) (number? b))
+                     (if (or (flonum? a) (flonum? b))
+                         (fl* (real->flonum a) (real->flonum b))
+                         (* a b))
+                     (jolt-mul a b))))
+    ((_ a b c ...) (jolt-n* (jolt-n* a b) c ...))))
+(define-syntax jolt-n-div
+  (syntax-rules ()
+    ((_) (jolt-div))
+    ((_ a) (jolt-div a))
+    ((_ a b) (jolt-div2 a b))
+    ((_ a b c ...) (jolt-n-div (jolt-div2 a b) c ...))))
+(define-syntax define-n-cmp
+  (syntax-rules ()
+    ((_ name op op2)
+     (define-syntax name
+       (syntax-rules ()
+         ((_) (op2))
+         ((_ a) (begin a #t))
+         ((_ ea eb) (let ((a ea) (b eb))
+                      (if (and (number? a) (number? b)) (op a b) (op2 a b))))
+         ((_ ea eb c (... ...)) (let ((a ea) (b eb))
+                                  (and (name a b) (name b c (... ...))))))))))
+(define-n-cmp jolt-n<  <  jolt-lt2)
+(define-n-cmp jolt-n>  >  jolt-gt2)
+(define-n-cmp jolt-n<= <= jolt-le2)
+(define-n-cmp jolt-n>= >= jolt-ge2)
+(define-syntax jolt-n-min
+  (syntax-rules ()
+    ((_) (jolt-min))
+    ((_ a) (jolt-min a))
+    ((_ a b) (jolt-min2 a b))
+    ((_ a b c ...) (jolt-n-min (jolt-min2 a b) c ...))))
+(define-syntax jolt-n-max
+  (syntax-rules ()
+    ((_) (jolt-max))
+    ((_ a) (jolt-max a))
+    ((_ a b) (jolt-max2 a b))
+    ((_ a b c ...) (jolt-n-max (jolt-max2 a b) c ...))))
 
 ;; --- unchecked (Java long) arithmetic: wrap to signed 64 bits ----------------
 ;; Clojure's unchecked-* (and +/-/* under *unchecked-math*) are long ops that
@@ -244,11 +445,26 @@
 ;; can't statically resolve to a procedure (a keyword/coll/proc held in a local)
 ;; routes here. Off the arithmetic/self-recursion hot path by construction.
 ;; ============================================================================
+;; (pred . handler) arms making a host type invocable; handler gets (f args).
+(define jolt-invoke-arms '())
+(define (register-invoke-arm! pred handler)
+  (set! jolt-invoke-arms (cons (cons pred handler) jolt-invoke-arms)))
+(define (jolt-invoke-arm-for f)
+  (let loop ((as jolt-invoke-arms))
+    (cond ((null? as) #f)
+          (((caar as) f) (cdar as))
+          (else (loop (cdr as))))))
+
 (define (jolt-invoke f . args)
   (cond
     ((procedure? f) (apply f args))
     ((keyword? f) (apply jolt-get (car args) f (cdr args)))   ; (:k m [d]) -> (get m :k [d])
     ((jolt-symbol? f) (apply jolt-get (car args) f (cdr args)))   ; ('s m [d]) -> (get m 's [d])
+    ;; a VECTOR invokes as nth (a bad index throws, like IPersistentVector.invoke);
+    ;; maps and sets invoke as get.
+    ((pvec? f) (if (and (pair? args) (null? (cdr args)))
+                   (jolt-nth f (car args))
+                   (apply jolt-get f args)))
     ((jolt-coll? f) (apply jolt-get f args))                  ; (coll k [d]) -> (get coll k [d])
     ((jolt-transient? f) (apply jolt-get f args))             ; a transient vec/map/set is callable on the JVM
     ;; a record/reify implementing clojure.lang.IFn is callable: dispatch to its
@@ -257,6 +473,9 @@
      => (lambda (m) (apply jolt-invoke m f args)))
     ((and (reified-methods f) (hashtable-ref (reified-methods f) "invoke" #f))
      => (lambda (m) (apply jolt-invoke m f args)))
+    ;; host types registered as callable (promise delivers, …): consulted only
+    ;; after every built-in case missed, so the hot dispatch pays nothing.
+    ((jolt-invoke-arm-for f) => (lambda (h) (h f args)))
     ;; calling a non-fn: a ClassCastException naming the operator's CLASS (like
     ;; the JVM's "class clojure.lang.LazySeq cannot be cast to ... IFn" — never
     ;; the value, whose printed form may be unbounded: ((range)) must throw, not
@@ -442,8 +661,14 @@
 ;; falls back to a copy-on-write wrapper for other targets (lists, sorted colls,
 ;; nil), so those keep the old per-step jolt-conj behaviour.
 (define (jolt-into to from)
-  (meta-carry to
-    (jolt-persistent! (reduce-seq (lambda (t x) (jolt-conj! t x)) (jolt-transient-new to) (jolt-seq from)))))
+  ;; only an editable collection rides the transient path; anything else
+  ;; (PersistentQueue, sorted colls, seqs) folds through conj, like RT's
+  ;; instanceof IEditableCollection split.
+  (if (or (pvec? to) (pmap? to) (pset? to))
+      (meta-carry to
+        (jolt-persistent! (reduce-seq (lambda (t x) (jolt-conj! t x)) (jolt-transient-new to) (jolt-seq from))))
+      (meta-carry to
+        (reduce-seq (lambda (acc x) (jolt-conj1 acc x)) to (jolt-seq from)))))
 
 (define (range-from n) (cseq-lazy n (lambda () (range-from (+ n 1)))))
 ;; A bounded range is a real chunked-seq, like clojure.lang.LongRange: eager, with
@@ -548,8 +773,14 @@
 ;; Parity over the full integer range (JVM even?/odd? accept any integer,
 ;; bignums included); a fixnum-only fxand crashes on a large value (e.g. a hash).
 (define (parity-int n) (if (flonum? n) (exact (floor n)) n))
-(define (jolt-even? n) (even? (parity-int n)))
-(define (jolt-odd? n) (odd? (parity-int n)))
+(define (jolt-parity-check n)
+  (unless (and (number? n) (exact? n) (integer? n))
+    (jolt-throw (jolt-host-throwable
+                 "java.lang.IllegalArgumentException"
+                 (string-append "Argument must be an integer: "
+                                (guard (e (#t "?")) (jolt-str n)))))))
+(define (jolt-even? n) (jolt-parity-check n) (even? (parity-int n)))
+(define (jolt-odd? n) (jolt-parity-check n) (odd? (parity-int n)))
 (define (jolt-pos? n) (> n 0))
 (define (jolt-neg? n) (< n 0))
 (define (jolt-zero? n) (= n 0))
@@ -558,8 +789,18 @@
 ;; ============================================================================
 ;; keys / vals — return seqs (nil on the empty map), HAMT-iteration order
 ;; ============================================================================
-(define (jolt-keys m) (if (jolt-nil? m) jolt-nil (list->cseq (pmap-fold m (lambda (k v a) (cons k a)) '()))))
-(define (jolt-vals m) (if (jolt-nil? m) jolt-nil (list->cseq (pmap-fold m (lambda (k v a) (cons v a)) '()))))
+;; keys/vals of anything empty is nil (RT.keys over a nil seq); a non-empty
+;; non-map still fails (its elements are not MapEntries).
+(define (jolt-keys m)
+  (cond ((jolt-nil? m) jolt-nil)
+        ((pmap? m) (list->cseq (pmap-fold m (lambda (k v a) (cons k a)) '())))
+        ((jolt-nil? (jolt-seq m)) jolt-nil)
+        (else (list->cseq (pmap-fold m (lambda (k v a) (cons k a)) '())))))
+(define (jolt-vals m)
+  (cond ((jolt-nil? m) jolt-nil)
+        ((pmap? m) (list->cseq (pmap-fold m (lambda (k v a) (cons v a)) '())))
+        ((jolt-nil? (jolt-seq m)) jolt-nil)
+        (else (list->cseq (pmap-fold m (lambda (k v a) (cons v a)) '())))))
 
 ;; ============================================================================
 ;; sequential equality + hash (hooks called from values.ss / collections.ss);

host/chez/smoke.sh

@@ -30,6 +30,39 @@ check_loc() {
   fi
 }
 
+# An uncaught error's stack trace must name the runtime-eval'd fn frames that
+# survive TCO (the non-tail spine), even though the eval path registers no source
+# map — "print what is available". Asserts a substring appears under "  trace:".
+check_trace() {
+  err="$(bin/joltc -e "$1" 2>&1 >/dev/null)"
+  if printf '%s' "$err" | grep -q '  trace:' && printf '%s' "$err" | grep -q "$2"; then
+    pass=$((pass + 1))
+  else
+    echo "  FAIL (trace): $1"
+    echo "    want stderr trace to contain \`$2\`, got \`$err\`"
+    fails=$((fails + 1))
+  fi
+}
+
+# JOLT_TRACE opts into the tail-frame history (the ring of rings): every $2 (an
+# ERE) must match the "  trace:" block. Used to assert TCO-elided frames are
+# recovered and non-tail caller context survives a tail loop.
+check_trace_on() {
+  err="$(JOLT_TRACE=1 bin/joltc -e "$1" 2>&1 >/dev/null)"
+  ok=1
+  printf '%s' "$err" | grep -q '  trace:' || ok=0
+  shift
+  for want in "$@"; do
+    printf '%s' "$err" | grep -Eq "$want" || ok=0
+  done
+  if [ "$ok" = 1 ]; then
+    pass=$((pass + 1))
+  else
+    echo "  FAIL (trace-on): want [$*] in trace, got \`$err\`"
+    fails=$((fails + 1))
+  fi
+}
+
 check '(+ 1 2)' '3'
 check '(defn fib [n] (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2))))) (fib 15)' '610'
 check '(->> (range 10) (filter even?) (map (fn [x] (* x x))) (reduce +))' '120'
@@ -60,6 +93,53 @@ check '(try (load-string "(+") (catch :default e (ex-message e)))' 'EOF while re
 check_loc '(throw (ex-info "boom" {}))' 'boom'
 check_loc '(do (+ 1 1) (/ 1 0))' '  at 1:'
 
+# Runtime-eval'd fns aren't source-mapped, but their native frame names survive on
+# the non-tail spine; the trace must show them. deepest/+ are tail calls (erased);
+# middle and outer wait on a non-tail (inc …) so their frames are live at the throw.
+trace_prog='(defn deepest [x] (+ x 1)) (defn middle [x] (inc (deepest x))) (defn outer [x] (inc (middle x))) (outer :nan)'
+check_trace "$trace_prog" 'middle'
+check_trace "$trace_prog" 'outer'
+
+# JOLT_TRACE (tail-frame history / ring of rings). An all-tail chain is entirely
+# TCO-erased from the continuation, but the history recovers every frame — incl.
+# `deepest`, the actual error site.
+check_trace_on '(defn deepest [x] (+ x 1)) (defn middle [x] (deepest x)) (defn outer [x] (middle x)) (outer :nan)' \
+  'deepest' 'middle' 'outer'
+# A tail loop (a<->b) under a NON-tail caller: the loop is confined to one rib's
+# bounded inner ring, so the caller context (`driver`, `top`) is NOT flushed out —
+# the point of the ring of rings.
+check_trace_on '(declare b) (defn a [n] (if (zero? n) (+ :x 1) (b (dec n)))) (defn b [n] (a n)) (defn driver [] (inc (a 6))) (defn top [] (inc (driver))) (top)' \
+  'driver' 'top'
+# A ^long/^double return hint wraps the body in a coercion, so the hinted fn's call
+# is NOT a tail call — its own frame is still live and must appear (not be elided).
+check_trace_on '(defn g [n] (+ :x n)) (defn ^long f [n] (g n)) (f 3)' 'f' 'g'
+# History is per top-level form: a later form's error trace shows its own frames
+# (h2/u2), not frames from an earlier, already-returned form (h1/u1).
+check_trace_on '(defn h1 [x] (inc x)) (defn u1 [] (inc (h1 5))) (u1) (defn h2 [x] (+ :x x)) (defn u2 [] (inc (h2 5))) (u2)' \
+  'h2' 'u2'
+err_stale="$(JOLT_TRACE=1 bin/joltc -e '(defn h1 [x] (inc x)) (defn u1 [] (inc (h1 5))) (u1) (defn h2 [x] (+ :x x)) (defn u2 [] (inc (h2 5))) (u2)' 2>&1 >/dev/null)"
+if printf '%s' "$err_stale" | grep -q 'h1'; then
+  echo "  FAIL (trace-on): stale frame h1 from an earlier form leaked into the trace"
+  fails=$((fails + 1))
+else
+  pass=$((pass + 1))
+fi
+# A file-backed project run maps each runtime-compiled frame to ns/name (file:line)
+# — the eval path registers source in trace mode, so the trace isn't bare names.
+tr_proj="$(mktemp -d)"
+mkdir -p "$tr_proj/src/tp"
+printf '{:paths ["src"] :aliases {:run {:main-opts ["-m" "tp.core"]}}}\n' > "$tr_proj/deps.edn"
+printf '(ns tp.core)\n(defn deep [x] (+ x 1))\n(defn mid [x] (inc (deep x)))\n(defn -main [& _] (mid :nan))\n' > "$tr_proj/src/tp/core.clj"
+tr_out="$(JOLT_TRACE=1 JOLT_PWD="$tr_proj" bin/joltc -M:run 2>&1)"
+if printf '%s' "$tr_out" | grep -Eq 'tp\.core/deep \(.*/tp/core\.clj:2\)'; then
+  pass=$((pass + 1))
+else
+  echo "  FAIL: JOLT_TRACE trace should map a frame to ns/name (file:line)"
+  printf '%s\n' "$tr_out" | sed 's/^/    | /'
+  fails=$((fails + 1))
+fi
+rm -rf "$tr_proj"
+
 # --help prints usage, and lists the nREPL server under its real flag name.
 help_out="$(bin/joltc --help 2>/dev/null)"
 if printf '%s' "$help_out" | grep -q -- '--nrepl-server'; then
@@ -159,5 +239,25 @@ else
   fails=$((fails + 1))
 fi
 
+# REPL-driven development traces by default: an error in an evaluated form shows a
+# tail-frame backtrace with no JOLT_TRACE set. rb tail-calls ra tail-calls +, all
+# TCO-elided from the continuation — only the history recovers them.
+repl_err="$(printf '(defn ra [x] (+ x 1))\n(defn rb [x] (ra x))\n(rb :nan)\n:exit\n' | bin/joltc repl 2>&1)"
+if printf '%s' "$repl_err" | grep -q '  trace:' && printf '%s' "$repl_err" | grep -q 'rb'; then
+  pass=$((pass + 1))
+else
+  echo "  FAIL: a REPL error should show a tail-frame trace by default"
+  printf '%s\n' "$repl_err" | sed 's/^/    | /'
+  fails=$((fails + 1))
+fi
+# JOLT_TRACE=0 opts out — no trace in the REPL.
+repl_off="$(printf '(defn ra [x] (+ x 1))\n(defn rb [x] (ra x))\n(rb :nan)\n:exit\n' | JOLT_TRACE=0 bin/joltc repl 2>&1)"
+if printf '%s' "$repl_off" | grep -q '  trace:'; then
+  echo "  FAIL: JOLT_TRACE=0 should suppress the REPL trace"
+  fails=$((fails + 1))
+else
+  pass=$((pass + 1))
+fi
+
 echo "cli smoke: $pass passed, $fails failed"
 [ "$fails" -eq 0 ]

host/chez/source-registry.ss

@@ -57,10 +57,36 @@
                       ((symbol? nm) (symbol->string nm))
                       (else #f)))))))
 
-;; Walk a continuation, returning the registered jolt frames (innermost first) as
-;; (frame-name . record) pairs, where record is #(ns name file line) or the symbol
-;; 'ambiguous. Unmapped frames (host spine, anonymous lambdas) are skipped; raw
-;; depth is capped.
+;; Frame names that are pure Chez / jolt-runtime plumbing — the eval boundary,
+;; the var-cell trampoline, continuation/winder internals. They carry no Clojure
+;; meaning, so an unmapped frame with one of these names is dropped from the trace
+;; (a MAPPED frame is always kept — a jolt fn that happens to share the name still
+;; resolves to its source). Any name Chez prefixes with `$` (system) or that jolt
+;; prefixes with `jolt-` (host runtime) is plumbing too.
+(define srcreg-plumbing-names
+  (let ((h (make-hashtable string-hash string=?)))
+    (for-each (lambda (s) (hashtable-set! h s #t))
+              '("dynamic-wind" "winder-dummy" "ksrc" "invoke" "apply"
+                "call-with-values" "call/cc" "call-with-current-continuation"
+                "raise" "raise-continuable" "with-exception-handler" "guard"
+                "eval" "compile" "interpret" "expand" "read" "load"
+                ;; host dispatch/coercion helpers (not `jolt-` prefixed) that carry
+                ;; no Clojure meaning in a trace
+                "record-method-dispatch" "protocol-resolve" "devirt-resolve"
+                "list->cseq" "host-static-call" "host-call"))
+    h))
+(define (srcreg-plumbing-name? nm)
+  (or (hashtable-ref srcreg-plumbing-names nm #f)
+      (and (fx>? (string-length nm) 0) (char=? (string-ref nm 0) #\$))
+      (and (fx>=? (string-length nm) 5) (string=? (substring nm 0 5) "jolt-"))))
+
+;; Walk a continuation, returning its frames (innermost first) as (frame-name .
+;; record) pairs. record is a source vector #(ns name file line) for a frame that
+;; maps to registered Clojure source, the symbol 'ambiguous for a short name shared
+;; across namespaces, or #f for an unmapped-but-named frame (the common case on the
+;; open-world eval path, where nothing is registered — the bare frame name is still
+;; a useful trace line). Plumbing frames (host spine, eval boundary) and unnamed
+;; frames are skipped; raw depth is capped.
 (define (jolt-frame-records k)
   ;; read the env at call time, not load time: a built binary runs top-level forms
   ;; at heap-build time, where this would always be unset.
@@ -70,39 +96,84 @@
       (if (or (not io) (fx>=? n 400))
           (reverse acc)
           (let* ((nm (srcreg-frame-name io))
-                 (src (and nm (hashtable-ref source-registry nm #f))))
+                 (src (and nm (hashtable-ref source-registry nm #f)))
+                 ;; keep a frame that maps, or any named frame that isn't plumbing
+                 (keep? (and nm (or src (not (srcreg-plumbing-name? nm))))))
             (when (and debug? nm)
-              (display (string-append "  [frame] " nm (if src " *MAPPED*" "") "\n")
+              (display (string-append "  [frame] " nm (if src " *MAPPED*"
+                                                          (if keep? "" " (skipped)")) "\n")
                        (current-error-port)))
             (loop (guard (e (#t #f)) (io 'link)) (fx+ n 1)
-                  (if src (cons (cons nm src) acc) acc))))))))
+                  (if keep? (cons (cons nm src) acc) acc))))))))
+
+;; Render a list of (frame-name . record) pairs (innermost/deepest first) to a
+;; backtrace string. record is a source vector #(ns name file line) -> "ns/name
+;; (file:line)", or 'ambiguous / #f -> the bare frame name. A run of the same
+;; frame-name collapses to one "name (xN)" line (deep recursion, or a hot fn a
+;; loop re-enters), and the number of distinct lines is capped.
+(define (jolt-render-recs recs)
+  (let ((port (open-output-string)))
+    (let loop ((rs recs) (shown 0))
+      (if (or (null? rs) (fx>=? shown 30))
+          (get-output-string port)
+          (let* ((p (car rs)) (frame-name (car p)) (r (cdr p)))
+            ;; count a maximal run of the same frame-name
+            (let run ((tail (cdr rs)) (cnt 1))
+              (if (and (pair? tail) (string=? (car (car tail)) frame-name))
+                  (run (cdr tail) (fx+ cnt 1))
+                  (begin
+                    (put-string port "    ")
+                    (if (vector? r)
+                        (let ((ns (vector-ref r 0)) (nm (vector-ref r 1))
+                              (file (vector-ref r 2)) (line (vector-ref r 3)))
+                          (put-string port ns) (put-string port "/") (put-string port nm)
+                          (when (string? file)
+                            (put-string port " (") (put-string port file)
+                            (put-string port ":") (put-string port (number->string line))
+                            (put-string port ")")))
+                        (put-string port frame-name))   ; 'ambiguous / unmapped: bare name
+                    (when (fx>? cnt 1)
+                      (put-string port " (x") (put-string port (number->string cnt)) (put-string port ")"))
+                    (put-char port #\newline)
+                    (loop tail (fx+ shown 1))))))))))
+
+;; Multi-line backtrace for an uncaught value. Two sources, in preference order:
+;;   1. The tail-frame history ring (rt.ss), when JOLT_TRACE enabled it — an
+;;      execution history of the runtime-compiled fns entered before the throw,
+;;      INCLUDING ones TCO erased from the live continuation. Most-recent first.
+;;   2. Otherwise the live continuation (jolt-frame-records) — the accurate but
+;;      TCO-truncated non-tail spine.
+;; Each frame maps to "ns/name (file:line)" when registered, else its bare name.
+;; #f when neither source yields a frame (the caller then prints just the location).
+;; The tail-frame history ring rendered as a backtrace, or #f when tracing is off /
+;; empty. A mapped frame is kept; else drop plumbing (same rule as the continuation
+;; path) so the two sources read consistently.
+(define (jolt-history-backtrace)
+  (let* ((hist (jolt-trace-snapshot))
+         (recs (let loop ((ns hist) (acc '()))
+                 (if (null? ns)
+                     (reverse acc)
+                     (let* ((nm (car ns)) (src (hashtable-ref source-registry nm #f)))
+                       (loop (cdr ns)
+                             (if (or src (not (srcreg-plumbing-name? nm)))
+                                 (cons (cons nm src) acc) acc)))))))
+    (and (pair? recs) (jolt-render-recs recs))))
 
-;; Multi-line backtrace for an uncaught value — "  ns/name (file:line)" for a
-;; mapped frame, the bare frame name for an ambiguous one — or #f when no jolt
-;; frame maps (the caller then prints just the top-level location). Capped to the
-;; innermost frames.
 (define (jolt-backtrace-string v)
-  (let ((k (jolt-error-continuation v)))
-    (and k
-         (let ((recs (jolt-frame-records k)))
-           (and (pair? recs)
-                (let ((port (open-output-string)))
-                  (let loop ((rs recs) (shown 0))
-                    (when (and (pair? rs) (fx<? shown 30))
-                      (let* ((p (car rs)) (frame-name (car p)) (r (cdr p)))
-                        (put-string port "    ")
-                        (if (vector? r)
-                            (let ((ns (vector-ref r 0)) (nm (vector-ref r 1))
-                                  (file (vector-ref r 2)) (line (vector-ref r 3)))
-                              (put-string port ns) (put-string port "/") (put-string port nm)
-                              (when (string? file)
-                                (put-string port " (") (put-string port file)
-                                (put-string port ":") (put-string port (number->string line))
-                                (put-string port ")")))
-                            (put-string port frame-name))   ; 'ambiguous: bare name
-                        (put-char port #\newline))
-                      (loop (cdr rs) (fx+ shown 1))))
-                  (get-output-string port)))))))
+  (or (jolt-history-backtrace)
+      (let ((k (jolt-error-continuation v)))
+        (and k
+             (let ((recs (jolt-frame-records k)))
+               (and (pair? recs) (jolt-render-recs recs)))))))
+
+;; Exposed for the REPL / nREPL error paths, which catch errors themselves instead
+;; of going through the uncaught reporter. Returns the "  trace:\n<frames>" block
+;; from the tail-frame HISTORY only — the live continuation in a REPL is just the
+;; REPL's own machinery — or nil when tracing is off (so a caller can when-let).
+(def-var! "jolt.host" "backtrace-string"
+  (lambda ()
+    (let ((bt (jolt-history-backtrace)))
+      (if bt (string-append "  trace:\n" bt) jolt-nil))))
 
 ;; Render an uncaught jolt throw (any value, not just a Chez condition) to a port:
 ;; an ex-info shows its message + ex-data (+ a host cause); anything else is

host/chez/stub/launcher.c

@@ -26,6 +26,12 @@ static int self_path(char *buf, uint32_t size) {
   /* _NSGetExecutablePath fills buf and reports the needed size on overflow. */
   return _NSGetExecutablePath(buf, &size);
 }
+#elif defined(_WIN32)
+#include <windows.h>
+static int self_path(char *buf, uint32_t size) {
+  DWORD n = GetModuleFileNameA(NULL, buf, size);
+  return (n == 0 || n >= size) ? -1 : 0;
+}
 #else
 #include <unistd.h>
 static int self_path(char *buf, uint32_t size) {

host/chez/transients.ss

@@ -44,7 +44,16 @@
      (let ((ht (make-hashtable key-hash jolt=2)))
        (pset-fold coll (lambda (e acc) (hashtable-set! ht e #t) acc) 0)
        (make-jolt-transient 'set ht 0 #t #f)))
-    (else (make-jolt-transient 'cow coll 0 #t #f))))
+    ;; RFC 0003: any COLLECTION transients (the sorted/list/seq superset rides
+    ;; the copy-on-write fallback); a non-collection is the JVM's cast failure.
+    ((or (cseq? coll) (empty-list-t? coll) (jolt-lazyseq? coll)
+         (htable? coll) (jrec? coll))
+     (make-jolt-transient 'cow coll 0 #t #f))
+    (else
+     (jolt-throw (jolt-host-throwable
+                  "java.lang.ClassCastException"
+                  (string-append "class " (guard (e (#t "?")) (jolt-class-name coll))
+                                 " cannot be cast to class clojure.lang.IEditableCollection"))))))
 
 ;; map put/delete that maintain the reverse insertion-order list in `ord`.
 (define (tmap-put! t k v)
@@ -77,7 +86,11 @@
                (if (fx<? i cnt) (begin (vector-set! out i (vector-ref buf i)) (loop (fx+ i 1)))
                    (make-pvec out)))))))
     ((map)
-     (let* ((ht (jolt-transient-buf t)) (cnt (hashtable-size ht)) (cap (jolt-transient-n t)))
+     (let* ((ht (jolt-transient-buf t)) (cnt (hashtable-size ht)) (cap (jolt-transient-n t))
+            ;; Clojure 1.13: a keyword-only map stays an array map up to 64 entries,
+            ;; so a keyword map built through a transient (into {} …) keeps insertion
+            ;; order to 64, matching the literal/assoc paths.
+            (cap (if (all-keywords? (jolt-transient-ord t)) (fxmax array-map-limit-kw cap) cap)))
        (if (fx>? cnt cap)
            ;; promoted past the array capacity: hash order
            (let ((m empty-pmap-hash))

jolt-core/clojure/core/00-syntax.clj

@@ -188,9 +188,23 @@
                      [false nil]
                      (if or-map (keys or-map) [])))
          amp? (fn* [x] (and (symbol? x) (= "&" (name x))))
+         ;; split a :keys/:syms/:strs name list at & into [sym bind?] pairs. Names
+         ;; before & bind normally (bind? true); names after & are declared-only
+         ;; (bind? false) — accepted keys (:keys) or required keys (:keys!), per
+         ;; CLJ-2961.
+         classify
+           (fn* [names]
+             (nth (reduce (fn* [st x]
+                            (if (amp? x)
+                              [(nth st 0) false]
+                              [(conj (nth st 0) [x (nth st 1)]) (nth st 1)]))
+                          [[] true] names)
+                  0))
          proc
            (fn* proc [pat init acc]
              (cond
+               ;; CLJ-2954: & is reserved for destructuring rest, never a binding.
+               (amp? pat) (throw (new IllegalArgumentException "Can't use & as a local binding"))
                (symbol? pat) (conj (conj acc pat) init)
                (vector? pat)
                  (let* [g (symbol (str (gensym)))
@@ -231,30 +245,45 @@
                         ;; group binds a :keys/:strs/:syms list. dnsp is the destructuring
                         ;; namespace from a qualified key like :ns/keys — it both prefixes
                         ;; the lookup key and overrides a bare symbol's namespace.
+                        ;; group binds a :keys/:strs/:syms list. checked? marks the
+                        ;; :keys!/:strs!/:syms! variants (CLJ-2961): lookups use req!
+                        ;; (throw on missing) instead of get. A pair is [sym bind?];
+                        ;; bind? false (names after &) is declared-only — for checked
+                        ;; groups it still runs req! (bound to a throwaway gensym) to
+                        ;; enforce the key, for unchecked groups it's a no-op.
                         group
-                          (fn* group [a names kind dnsp]
+                          (fn* group [a names kind dnsp checked?]
                             (if names
                                 (reduce
                                   ;; s is a symbol (a b) or a keyword (:a :b); name/
                                   ;; namespace handle both, so :keys [:major] binds
                                   ;; `major` looking up :major (str would keep the colon).
-                                  (fn* [aa s]
-                                    (let* [local (name s)
+                                  (fn* [aa pair]
+                                    (let* [s (nth pair 0)
+                                           bind? (nth pair 1)
+                                           local (name s)
                                            nsp (or (namespace s) dnsp)
                                            keyform (cond
                                                      (= kind :kw) (keyword (if nsp (str nsp "/" local) local))
                                                      (= kind :str) local
                                                      :else `(quote ~(symbol nsp local)))
-                                           fo (find-or or-map local)]
-                                      (conj (conj aa (symbol local))
-                                            (if (nth fo 0)
-                                              `(get ~gm ~keyform ~(nth fo 1))
-                                              `(get ~gm ~keyform)))))
-                                  a names)
+                                           fo (find-or or-map local)
+                                           lookup (cond
+                                                    checked? `(req! ~gm ~keyform)
+                                                    (nth fo 0) `(get ~gm ~keyform ~(nth fo 1))
+                                                    :else `(get ~gm ~keyform))]
+                                      (cond
+                                        bind?    (conj (conj aa (symbol local)) lookup)
+                                        checked? (conj (conj aa (symbol (str (gensym)))) lookup)
+                                        :else    aa)))
+                                  a (classify names))
                                 a))
-                        g1 (group base (get pat :keys) :kw nil)
-                        g2 (group g1 (get pat :strs) :str nil)
-                        g3 (group g2 (get pat :syms) :sym nil)]
+                        g1 (group base (get pat :keys)  :kw  nil false)
+                        g2 (group g1   (get pat :strs)  :str nil false)
+                        g3 (group g2   (get pat :syms)  :sym nil false)
+                        g4 (group g3   (get pat :keys!) :kw  nil true)
+                        g5 (group g4   (get pat :strs!) :str nil true)
+                        g6 (group g5   (get pat :syms!) :sym nil true)]
                    ;; remaining keys: a qualified :ns/keys|:ns/strs|:ns/syms groups under
                    ;; its namespace; any other keyword is skipped; a non-keyword is a
                    ;; nested binding pattern.
@@ -262,9 +291,12 @@
                              (if (keyword? k)
                                (let* [kn (name k) kns (namespace k)]
                                  (cond
-                                   (and kns (= kn "keys")) (group a (get pat k) :kw kns)
-                                   (and kns (= kn "strs")) (group a (get pat k) :str kns)
-                                   (and kns (= kn "syms")) (group a (get pat k) :sym kns)
+                                   (and kns (= kn "keys"))  (group a (get pat k) :kw  kns false)
+                                   (and kns (= kn "strs"))  (group a (get pat k) :str kns false)
+                                   (and kns (= kn "syms"))  (group a (get pat k) :sym kns false)
+                                   (and kns (= kn "keys!")) (group a (get pat k) :kw  kns true)
+                                   (and kns (= kn "strs!")) (group a (get pat k) :str kns true)
+                                   (and kns (= kn "syms!")) (group a (get pat k) :sym kns true)
                                    :else a))
                                ;; a direct binding {x :x}: apply its :or default
                                ;; (keyed by the local symbol) when the key is absent.
@@ -273,7 +305,7 @@
                                            `(get ~gm ~(get pat k) ~(nth fo 1))
                                            `(get ~gm ~(get pat k)))
                                        a))))
-                           g3 (keys pat)))
+                           g6 (keys pat)))
                :else (throw (str "unsupported destructuring pattern: " (pr-str pat)))))
          ploop
            (fn* ploop [i acc]
@@ -545,6 +577,8 @@
 ;; name binds only in the taken branch (temp# tests the value); via `let` so the
 ;; binding form may itself destructure, matching Clojure.
 (defmacro when-let [bindings & body]
+  (when (not= 2 (count bindings))
+    (throw (new IllegalArgumentException "when-let requires exactly 2 forms in binding vector")))
   (let [form (bindings 0) tst (bindings 1)]
     `(let [temp# ~tst]
        (if temp# (let [~form temp#] ~@body) nil))))

jolt-core/clojure/core/20-coll.clj

@@ -155,8 +155,43 @@
   (when-let [s (seq coll)]
     (or (pred (first s)) (recur pred (next s)))))
 
-(defn some-fn [& preds]
-  (fn [& xs] (some (fn [p] (some p xs)) preds)))
+;; Reference arities: at least one predicate ((some-fn) is an arity error), and
+;; the returned fn chains with or — a no-match result is the last predicate's
+;; own falsy value (false stays false, not nil).
+(defn some-fn
+  ([p]
+   (fn sp1
+     ([] nil)
+     ([x] (p x))
+     ([x y] (or (p x) (p y)))
+     ([x y z] (or (p x) (p y) (p z)))
+     ([x y z & args] (or (sp1 x y z)
+                         (some p args)))))
+  ([p1 p2]
+   (fn sp2
+     ([] nil)
+     ([x] (or (p1 x) (p2 x)))
+     ([x y] (or (p1 x) (p1 y) (p2 x) (p2 y)))
+     ([x y z] (or (p1 x) (p1 y) (p1 z) (p2 x) (p2 y) (p2 z)))
+     ([x y z & args] (or (sp2 x y z)
+                         (some (fn [q] (or (p1 q) (p2 q))) args)))))
+  ([p1 p2 p3]
+   (fn sp3
+     ([] nil)
+     ([x] (or (p1 x) (p2 x) (p3 x)))
+     ([x y] (or (p1 x) (p2 x) (p3 x) (p1 y) (p2 y) (p3 y)))
+     ([x y z] (or (p1 x) (p2 x) (p3 x) (p1 y) (p2 y) (p3 y) (p1 z) (p2 z) (p3 z)))
+     ([x y z & args] (or (sp3 x y z)
+                         (some (fn [q] (or (p1 q) (p2 q) (p3 q))) args)))))
+  ([p1 p2 p3 & ps]
+   (let [ps (cons p1 (cons p2 (cons p3 ps)))]
+     (fn spn
+       ([] nil)
+       ([x] (some (fn [p] (p x)) ps))
+       ([x y] (or (spn x) (spn y)))
+       ([x y z] (or (spn x) (spn y) (spn z)))
+       ([x y z & args] (or (spn x y z)
+                           (some (fn [p] (some p args)) ps)))))))
 
 (defn not-any? [pred coll] (not (some pred coll)))
 
@@ -184,7 +219,8 @@
 ;; compiler emit/inference path) — see predicates.ss.
 (defn ratio? [x]
   (and (number? x) (jolt.host/exact? x) (jolt.host/rational-type? x) (not (integer? x))))
-(defn rational? [x] (and (number? x) (jolt.host/exact? x)))
+(defn rational? [x]
+  (or (and (number? x) (jolt.host/exact? x)) (decimal? x)))
 ;; No first-class Class objects: class names are symbols the evaluator handles in
 ;; instance?/new positions, never values — so nothing is a class.
 (defn class? [x] false)
@@ -239,7 +275,8 @@
     (loop [i 0 s (seq coll)]
       (if (and s (< i n)) (recur (inc i) (next s)) i))))
 
-(defn run! [proc coll] (reduce (fn [_ x] (proc x) nil) nil coll) nil)
+;; the reducing fn returns proc's result, so a Reduced from proc short-circuits
+(defn run! [proc coll] (reduce (fn [_ x] (proc x)) nil coll) nil)
 
 (defn completing
   ([f] (completing f identity))
@@ -298,16 +335,28 @@
 (defn val [e] (if (map-entry? e) (nth e 1) (throw (ex-info "val requires a map entry" {}))))
 
 ;; --- Ad-hoc hierarchies (stage 3) — Clojure's canonical pure-map port. -----
-;; A hierarchy is {:parents {tag #{parents}} :ancestors {tag #{all}} 
+;; A hierarchy is {:parents {tag #{parents}} :ancestors {tag #{all}}
 ;; :descendants {tag #{all}}}. The 3-arity forms are PURE; the 1/2-arity forms
 ;; operate on the private global hierarchy atom. Multimethod dispatch
 ;; (evaluator defmulti-setup) calls isa? through the interned var.
+;;
+;; Ported from clojure.core with the reference's argument assertions and throw
+;; contracts intact — bad shapes throw exactly where they do there (a non-map h
+;; fails on the (parent-map tag) call, invalid tags fail the asserts). The class
+;; arms answer through the host class graph (jolt.host/class-* seams).
 
 (defn make-hierarchy []
   {:parents {} :descendants {} :ancestors {}})
 
 (def ^:private global-hierarchy (atom (make-hierarchy)))
 
+(defn- hier-assert [ok form]
+  (when-not ok (throw (new AssertionError (str "Assert failed: " form)))))
+
+;; a hierarchy tag naming a class — a class value, or the name string of a class
+;; the host graph models (jolt classes are their name strings).
+(defn- class-tag? [tag] (if (jolt.host/class-value? tag) true false))
+
 (defn isa?
   ([child parent] (isa? (deref global-hierarchy) child parent))
   ([h child parent]
@@ -316,6 +365,10 @@
        ;; so a class-keyed multimethod / (isa? (class x) C) dispatches like the JVM.
        (jolt.host/class-isa? child parent)
        (contains? (get (get h :ancestors) child #{}) parent)
+       ;; a hierarchy relationship established on one of a class's supers
+       (and (class-tag? child)
+            (some (fn [s] (contains? (get (get h :ancestors) s #{}) parent))
+                  (jolt.host/class-supers child)))
        (and (vector? parent) (vector? child)
             (= (count parent) (count child))
             (loop [ret true i 0]
@@ -325,24 +378,44 @@
 
 (defn parents
   ([tag] (parents (deref global-hierarchy) tag))
-  ([h tag] (not-empty (get (get h :parents) tag))))
+  ([h tag] (not-empty
+            (let [tp (get (get h :parents) tag)]
+              (if (class-tag? tag)
+                (into (set (jolt.host/class-bases tag)) tp)
+                tp)))))
 
 (defn ancestors
   ([tag] (ancestors (deref global-hierarchy) tag))
-  ([h tag]
-   ;; the user hierarchy plus any modeled JVM ancestry (jolt.host/class-ancestors)
-   ;; so (ancestors (class x)) answers like the JVM for the common interfaces.
-   (let [hier (get (get h :ancestors) tag)
-         host (jolt.host/class-ancestors tag)]
-     (not-empty (if host (into (or hier #{}) host) hier)))))
+  ([h tag] (not-empty
+            (let [ta (get (get h :ancestors) tag)]
+              (if (class-tag? tag)
+                ;; the class's own ancestry plus hierarchy relationships derived
+                ;; on the class or any of its supers
+                (let [superclasses (set (jolt.host/class-supers tag))]
+                  (reduce into superclasses
+                          (cons ta (map (fn [s] (get (get h :ancestors) s))
+                                        superclasses))))
+                ta)))))
 
 (defn descendants
   ([tag] (descendants (deref global-hierarchy) tag))
-  ([h tag] (not-empty (get (get h :descendants) tag))))
+  ([h tag] (if (class-tag? tag)
+             (throw (new UnsupportedOperationException "Can't get descendants of classes"))
+             (not-empty (get (get h :descendants) tag)))))
 
 (defn derive
-  ([tag parent] (swap! global-hierarchy derive tag parent) nil)
+  ([tag parent]
+   (hier-assert (namespace parent) "(namespace parent)")
+   (hier-assert (or (class-tag? tag)
+                    (and (or (keyword? tag) (symbol? tag)) (namespace tag)))
+                "(or (class? tag) (and (instance? clojure.lang.Named tag) (namespace tag)))")
+   (swap! global-hierarchy derive tag parent) nil)
   ([h tag parent]
+   (hier-assert (not= tag parent) "(not= tag parent)")
+   (hier-assert (or (class-tag? tag) (keyword? tag) (symbol? tag))
+                "(or (class? tag) (instance? clojure.lang.Named tag))")
+   (hier-assert (or (keyword? parent) (symbol? parent))
+                "(instance? clojure.lang.Named parent)")
    (let [tp (get h :parents)
          td (get h :descendants)
          ta (get h :ancestors)
@@ -350,14 +423,14 @@
               (reduce (fn [ret k]
                         (assoc ret k
                                (reduce conj (get targets k #{})
-                                       (cons target (get targets target)))))
-                      m (cons source (get sources source))))]
+                                       (cons target (targets target)))))
+                      m (cons source (sources source))))]
      (or
-      (when-not (contains? (get tp tag #{}) parent)
-        (when (contains? (get ta tag #{}) parent)
-          (throw (str tag " already has " parent " as ancestor")))
-        (when (contains? (get ta parent #{}) tag)
-          (throw (str "Cyclic derivation: " parent " has " tag " as ancestor")))
+      (when-not (contains? (tp tag) parent)
+        (when (contains? (ta tag) parent)
+          (throw (new Exception (str tag " already has " parent " as ancestor"))))
+        (when (contains? (ta parent) tag)
+          (throw (new Exception (str "Cyclic derivation: " parent " has " tag " as ancestor"))))
         {:parents (assoc tp tag (conj (get tp tag #{}) parent))
          :ancestors (tf ta tag td parent ta)
          :descendants (tf td parent ta tag td)})
@@ -367,15 +440,15 @@
   ([tag parent] (swap! global-hierarchy underive tag parent) nil)
   ([h tag parent]
    (let [parent-map (get h :parents)
-         childs-parents (if (get parent-map tag)
-                          (disj (get parent-map tag) parent)
+         childs-parents (if (parent-map tag)
+                          (disj (parent-map tag) parent)
                           #{})
          new-parents (if (not-empty childs-parents)
                        (assoc parent-map tag childs-parents)
                        (dissoc parent-map tag))
          deriv-seq (mapcat (fn [e] (cons (key e) (interpose (key e) (val e))))
                            (seq new-parents))]
-     (if (contains? (get parent-map tag #{}) parent)
+     (if (contains? (parent-map tag) parent)
        (reduce (fn [p [t pr]] (derive p t pr))
                (make-hierarchy) (partition 2 deriv-seq))
        h))))
@@ -386,7 +459,8 @@
 (defn sequential? [x] (or (vector? x) (seq? x)))
 (defn associative? [x] (or (map? x) (vector? x)))
 (defn counted? [x]
-  (or (vector? x) (map? x) (set? x) (list? x) (string? x)))
+  ;; a String is not Counted on the JVM (count works via CharSequence, not O(1))
+  (or (vector? x) (map? x) (set? x) (list? x)))
 (defn indexed? [x] (vector? x))
 ;; sorted? is defined by the next tier (25-sorted) — declared here so this
 ;; tier compiles (forward references are analysis errors).
@@ -394,7 +468,7 @@
 
 (defn reversible? [x] (or (vector? x) (sorted? x)))
 (defn seqable? [x]
-  (or (nil? x) (coll? x) (string? x)))
+  (if (or (nil? x) (coll? x) (string? x) (jolt.host/array-value? x)) true false))
 
 (defn boolean? [x] (or (true? x) (false? x)))
 (defn double? [x] (and (number? x) (not (integer? x))))

jolt-core/clojure/core/21-coll.clj

@@ -12,7 +12,8 @@
 ;; Clojure. Collections only — a string is seqable but not shuffleable, as on
 ;; the JVM (Collections/shuffle wants a Collection).
 (defn shuffle [coll]
-  (when-not (coll? coll)
+  ;; Collections/shuffle wants a java.util.Collection — a map is not one
+  (when (or (not (coll? coll)) (map? coll))
     (throw (ex-info (str "shuffle requires a collection, got: " coll) {})))
   (loop [v (vec coll) i (dec (count v))]
     (if (pos? i)
@@ -28,6 +29,10 @@
 (defn sort-by
   ([keyfn coll] (sort-by keyfn compare coll))
   ([keyfn comp coll]
+   ;; a collection is never a Comparator (the JVM cast would fail); catching it
+   ;; here beats silently "sorting" through coll-as-fn lookups
+   (when (coll? comp)
+     (throw (new ClassCastException (str (class comp) " cannot be cast to java.util.Comparator"))))
    (sort (fn [x y] (comp (keyfn x) (keyfn y))) coll)))
 
 ;; parse-uuid: nil unless s is a canonical 8-4-4-4-12 hex UUID string; throws
@@ -61,9 +66,10 @@
    \backspace "backspace" \space "space"})
 (defn char-name-string [c] (get char-name-strings c))
 
-;; Random selection over the host rand primitives.
+;; Random selection over the host rand primitives — the reference shape:
+;; nth directly (nil returns nil via RT.nth; a set throws like the JVM).
 (defn rand-nth [coll]
-  (let [v (vec coll)] (nth v (rand-int (count v)))))
+  (nth coll (rand-int (count coll))))
 
 (defn random-sample
   ([prob] (filter (fn [_] (< (rand) prob))))
@@ -133,8 +139,8 @@
          (concat (map first ss)
                  (apply interleave (map rest ss))))))))
 
-;; No ratio type on Jolt, so rationalize is identity.
-(defn rationalize [x] x)
+;; rationalize is host-native (java/bigdec.ss): a double routes through its
+;; shortest decimal print like BigDecimal.valueOf, so (rationalize 1.1) is 11/10.
 
 ;; 0-arg: a stateful transducer (tracks [seen? prev] in a volatile, so no sentinel
 ;; value is needed). 1-arg: eager dedupe of consecutive equal elements.
@@ -348,8 +354,8 @@
 (defn clojure-version [] "1.11.0-jolt")
 
 ;; bigdec is a host fn (host/chez/java/bigdec.ss) — a real BigDecimal value type.
-(defn numerator [x] (throw (ex-info "numerator requires a ratio (Jolt has no ratios)" {})))
-(defn denominator [x] (throw (ex-info "denominator requires a ratio (Jolt has no ratios)" {})))
+;; numerator/denominator are host natives (converters.ss) over Chez's exact
+;; rationals; a non-ratio is the Ratio cast failure.
 
 ;; jolt has no reflection, but a few common JVM interfaces carry a modeled
 ;; ancestry (jolt.host/class-supers) so reflective checks like

jolt-core/clojure/core/22-coll.clj

@@ -89,6 +89,21 @@
              (recur nxt (next ks))))
          m)))))
 
+(defn req!
+  "Returns the value mapped to key k in map m, like `get`, but throws
+  IllegalArgumentException when k is not present. Unlike `get`, does not nil-pun:
+  a key present with a nil value returns nil, an absent key throws. The primitive
+  behind checked-keys destructuring (:keys! / :syms! / :strs!)."
+  {:added "1.13"}
+  [m k]
+  ;; a fresh map is its own identity, so a present-but-nil value is distinguished
+  ;; from an absent key (same trick as get-in's sentinel).
+  (let [sentinel (hash-map)
+        v (get m k sentinel)]
+    (if (identical? sentinel v)
+      (throw (new IllegalArgumentException (str "Expected key: " k)))
+      v)))
+
 ;; find-based, so nil RESULTS are cached too; args canonicalize as a collection key.
 (defn memoize [f]
   (let [mem (atom (hash-map))]
@@ -136,6 +151,9 @@
     ;; a deftype/record with its own empty (IPersistentCollection) — e.g.
     ;; data.priority-map — uses it, before the generic map/set/vector arms.
     (jolt.host/jrec-method? coll "empty") (.empty coll)
+    ;; a defrecord without its own empty can't have one (RT: UnsupportedOperation)
+    (record? coll) (throw (new UnsupportedOperationException
+                               (str "Can't create empty: " (.getName (class coll)))))
     (sorted? coll) ((get (jolt.host/ref-get coll :ops) :empty) coll)
     (map? coll) (with-meta {} (meta coll))
     (set? coll) (with-meta #{} (meta coll))
@@ -183,10 +201,16 @@
      ([x y z & args] (f (apply g x y z args)))))
   ([f g & fs] (reduce comp (comp f g) fs)))
 
-;; Canonical IFn set: fns, keywords, symbols, maps (sorted incl.),
-;; sets, vectors, and vars — NOT lists ((ifn? '(1 2)) is false in Clojure).
+;; Canonical IFn set: fns, keywords, symbols, maps (sorted incl.), sets,
+;; vectors, vars — NOT lists ((ifn? '(1 2)) is false in Clojure) — plus the
+;; host callables (multimethods, promises) and a deftype/record implementing
+;; clojure.lang.IFn's invoke.
 (defn ifn? [x]
-  (or (fn? x) (keyword? x) (symbol? x) (map? x) (set? x) (vector? x) (var? x)))
+  (if (or (fn? x) (keyword? x) (symbol? x) (map? x) (set? x) (vector? x) (var? x)
+          (jolt.host/callable-host? x)
+          (jolt.host/jrec-method? x "invoke"))
+    true
+    false))
 
 ;; Auto-promoting (') and unchecked arithmetic. Jolt numbers don't overflow,
 ;; so all of these are the checked ops; fixed arities mirror Clojure's
@@ -198,10 +222,9 @@
 (def inc' inc)
 (def dec' dec)
 ;; unchecked-add / -subtract / -multiply / -negate / -inc / -dec (+ the -int
-;; variants) and -divide-int / -remainder-int are host-defined (host/chez/seq.ss):
-;; they WRAP to signed 64 bits like the JVM, which a plain (+ x y) overlay can't do.
-(defn unchecked-int [x] (int x))
-(def unchecked-long unchecked-int)
+;; variants), -divide-int / -remainder-int, and the unchecked-long/-int casts are
+;; host-defined (host/chez/seq.ss, converters.ss): they WRAP like the JVM
+;; primitive conversions, which a plain overlay over checked casts can't do.
 
 ;; int? is integer? on jolt: one number type, so fixed-precision and
 ;; arbitrary-precision integers coincide.
@@ -263,12 +286,14 @@
 
 (defn to-array-2d [coll] (to-array (map to-array coll)))
 
-;; Masking integer coercions (not aliases): byte/short wrap to their width.
-;; unchecked-byte/short truncate to a number; unchecked-char returns a char (as on
-;; the JVM). int handles chars, so (unchecked-byte \a) works.
-(defn unchecked-byte [x] (bit-and (int x) 0xff))
-(defn unchecked-short [x] (bit-and (int x) 0xffff))
-(defn unchecked-char [x] (char (bit-and (int x) 0xffff)))
+;; Wrapping (unchecked) coercions: truncate to the width and sign-fold like the
+;; JVM primitive conversions ((unchecked-byte 200) is -56); unchecked-char wraps
+;; into char range. unchecked-long/int are host natives (converters.ss).
+(defn unchecked-byte [x]
+  (let [b (bit-and (unchecked-long x) 0xff)] (if (< b 128) b (- b 256))))
+(defn unchecked-short [x]
+  (let [s (bit-and (unchecked-long x) 0xffff)] (if (< s 32768) s (- s 65536))))
+(defn unchecked-char [x] (char (bit-and (unchecked-long x) 0xffff)))
 (defn unchecked-float [x] (double x))
 (defn unchecked-double [x] (double x))
 
@@ -323,7 +348,8 @@
 ;; stays an unevaluated reader form on jolt and contains? can't see into it.
 (def ^:private special-syms
   #{'if 'do 'let* 'fn* 'quote 'var 'def 'loop* 'recur 'throw 'try 'catch
-    'finally 'new 'set! '. 'monitor-enter 'monitor-exit})
+    'finally 'new 'set! '. 'monitor-enter 'monitor-exit
+    '& 'case* 'deftype* 'letfn* 'reify*})
 
 (defn special-symbol? [s] (contains? special-syms s))
 
@@ -338,3 +364,14 @@
 (defn proxy-super [& args] (throw "proxy-super: JVM proxies are not supported in Jolt"))
 (defn construct-proxy [c & args] (throw "construct-proxy: not supported in Jolt"))
 (defn get-proxy-class [& interfaces] (throw "get-proxy-class: not supported in Jolt"))
+
+;; resolve, requiring the symbol's namespace first when it isn't loaded yet —
+;; the dynamic-require pattern (tooling, plugin registries). The require and
+;; resolve are the runtime fns, so this works identically under joltc run and
+;; in an AOT binary (which compiles the namespace from the source roots).
+(defn requiring-resolve [sym]
+  (if (qualified-symbol? sym)
+    (or (resolve sym)
+        (do (require (symbol (namespace sym)))
+            (resolve sym)))
+    (throw (new IllegalArgumentException (str "Not a qualified symbol: " sym)))))

jolt-core/clojure/core/30-macros.clj

@@ -28,11 +28,18 @@
   (let [args (if (string? (first args)) (rest args) args)
         args (if (and (map? (first args)) (not (symbol? (first args)))) (rest args) args)
         dispatch (first args)
-        opts (rest args)]
-    `(defmulti-setup (quote ~name) ~dispatch ~@opts)))
+        opts (rest args)
+        ;; qualify with the EXPANSION ns: a defmulti deferred inside a fn (a
+        ;; deftest body) must still define in the ns it was written in.
+        qname (symbol (str (clojure.core/ns-name clojure.core/*ns*))
+                      (clojure.core/name name))]
+    `(defmulti-setup (quote ~qname) ~dispatch ~@opts)))
 
 (defmacro defmethod [mm dispatch-val & fn-tail]
-  `(defmethod-setup (quote ~mm) ~dispatch-val (fn ~@fn-tail)))
+  ;; the expansion ns rides along so a deferred defmethod resolves its multifn
+  ;; against the ns it was written in (aliases and refers included).
+  `(defmethod-setup (quote ~mm) ~dispatch-val (fn ~@fn-tail)
+                    ~(str (clojure.core/ns-name clojure.core/*ns*))))
 
 ;; Multimethod table ops: a multimethod's method table lives on its
 ;; VAR (the value is just the dispatch closure), so these pass the name quoted
@@ -109,11 +116,15 @@
          (with-open ~(vec (drop 2 bindings)) ~@body)
          (finally (__close ~(first bindings)))))))
 
-;; jolt numbers are doubles — there is no BigDecimal math context, so the
-;; precision (and optional :rounding mode) is accepted and ignored.
+;; Binds *math-context*; BigDecimal arithmetic in the dynamic scope rounds its
+;; results to the precision with the rounding mode (default HALF_UP, like
+;; java.math.MathContext).
 (defmacro with-precision [precision & exprs]
-  (let [body (if (= :rounding (first exprs)) (drop 2 exprs) exprs)]
-    `(do ~@body)))
+  (let [[rounding body] (if (= :rounding (first exprs))
+                          [(second exprs) (drop 2 exprs)]
+                          ['HALF_UP exprs])]
+    `(binding [clojure.core/*math-context* {:precision ~precision :rounding '~rounding}]
+       ~@body)))
 
 (defmacro with-bindings [binding-map & body]
   `(with-bindings* ~binding-map (fn [] ~@body)))

jolt-core/jolt/backend_scheme.clj

@@ -17,13 +17,17 @@
 
 ;; Hot clojure.core primitives lowered to native Scheme.
 ;; `=` is the exactness-aware jolt= from values.ss; inc/dec/
-;; not are rt shims; mod/rem/quot map to Scheme's (Scheme has all three).
+;; not are rt shims. Arithmetic and comparisons lower to the jolt-n* checked
+;; macros (host/chez/seq.ss): the both-Chez-numbers fast path is open-coded and
+;; anything else (BigDecimal, a non-number) takes the Numbers.ops-style category
+;; dispatch, with JVM contagion (a double operand wins; an exact zero divisor is
+;; ArithmeticException; a double zero divisor is ##Inf/##NaN).
 (def ^:private native-ops
-  {"+" "+" "-" "-" "*" "*" "/" "/"
-   "<" "<" ">" ">" "<=" "<=" ">=" ">="
+  {"+" "jolt-n+" "-" "jolt-n-" "*" "jolt-n*" "/" "jolt-n-div"
+   "<" "jolt-n<" ">" "jolt-n>" "<=" "jolt-n<=" ">=" "jolt-n>="
    "=" "jolt=" "inc" "jolt-inc" "dec" "jolt-dec" "not" "jolt-not"
-   "min" "min" "max" "max"
-   "mod" "modulo" "rem" "remainder" "quot" "quotient"
+   "min" "jolt-n-min" "max" "jolt-n-max"
+   "mod" "jolt-mod" "rem" "jolt-rem" "quot" "jolt-quot"
    "vector" "jolt-vector" "hash-map" "jolt-hash-map-fn" "hash-set" "jolt-hash-set"
    "conj" "jolt-conj" "get" "jolt-get" "nth" "jolt-nth" "count" "jolt-count"
    "assoc" "jolt-assoc" "dissoc" "jolt-dissoc" "contains?" "jolt-contains?"
@@ -53,12 +57,12 @@
    "protocol-dispatch3" "protocol-dispatch3"})
 
 ;; Value-position resolution for a clojure.core ref passed AS A VALUE (to map /
-;; filter / reduce / apply). Arithmetic is the exception — Scheme's +/-/*// return
-;; EXACT results for exact/zero-arg inputs, breaking the all-double model in
-;; higher-order use, so value-position arithmetic routes to the flonum wrappers.
+;; filter / reduce / apply). The jolt-n* call-position forms are macros, so value
+;; position substitutes the variadic procedures over the same binary dispatch.
 (def ^:private core-value-procs
   (merge native-ops {"+" "jolt-add" "-" "jolt-sub" "*" "jolt-mul" "/" "jolt-div"
-                     "min" "jolt-min" "max" "jolt-max"}))
+                     "min" "jolt-min" "max" "jolt-max"
+                     "<" "jolt-lt" ">" "jolt-gt" "<=" "jolt-le" ">=" "jolt-ge"}))
 
 ;; Per-op arity gate: only lower when the Scheme prim and the jolt fn agree at
 ;; this arity. Ops absent from the table are variadic (legal at any arity).
@@ -83,7 +87,7 @@
 
 ;; jolt's comparison ops are vacuously true at arity 1 and DON'T inspect the arg,
 ;; but Scheme's < demands a number even there — special-case.
-(def ^:private cmp1-ops #{"<" ">" "<=" ">="})
+(def ^:private cmp1-ops #{"jolt-n<" "jolt-n>" "jolt-n<=" "jolt-n>="})
 
 ;; Host interop methods with a Chez RT shim (rt.ss jolt-host-call). A `.method`
 ;; call on any other method routes to record-method-dispatch (a reify/record
@@ -93,7 +97,7 @@
 ;; Native-op Scheme procedures that return a genuine Scheme boolean (#t/#f), so an
 ;; :if test built from them needs no jolt-truthy? wrapper.
 (def ^:private bool-returning-ops
-  #{"<" "<=" ">" ">=" "jolt=" "jolt-not"
+  #{"jolt-n<" "jolt-n<=" "jolt-n>" "jolt-n>=" "jolt=" "jolt-not"
     "jolt-even?" "jolt-odd?" "jolt-pos?" "jolt-neg?"
     "jolt-zero?" "jolt-empty?" "jolt-contains?" "jolt-nil?" "jolt-some?"})
 
@@ -168,6 +172,14 @@
 (def var-cache? (atom false))
 (defn set-var-cache! [on] (reset! var-cache? on))
 
+;; Opt-in tail-frame history (JOLT_TRACE): emit a (jolt-trace-push! "name") at the
+;; head of every named fn body, so an entry records the frame into the runtime ring
+;; buffer (rt.ss) and a TCO-elided frame still shows in an error's backtrace. OFF
+;; during the seed mint and `jolt build` (byte-determinism + no runtime cost);
+;; compile-eval.ss turns it on for runtime-eval'd user code when JOLT_TRACE is set.
+(def trace-frames? (atom false))
+(defn set-trace-frames! [on] (reset! trace-frames? on))
+
 ;; A direct-link Scheme binding name for a var. The fqn maps to a unique identifier
 ;; jv$<ns>$<name>; chars that break a Scheme identifier or the `$` separator are
 ;; escaped so distinct vars never collide.
@@ -187,6 +199,13 @@
 ;; recursion auto-restores them (no manual save/restore, no throw-leak).
 (def ^:dynamic *recur-target* nil)
 (def ^:dynamic *known-procs* #{})
+;; True while emitting a node in TAIL position. Only used, in trace mode, to mark a
+;; tail call so the runtime routes its callee into the current history rib instead
+;; of a new one (rt.ss). It never affects semantics — a wrong value only mislabels
+;; a debug trace line — so partial propagation is safe. `emit` (the wrapper below)
+;; clears it by default; the tail-transparent forms (fn body, if/do/let/loop) pass
+;; it to their tail child. Default false so a top-level form is treated non-tail.
+(def ^:dynamic *tail?* false)
 
 (def ^:private gensym-counter (atom 0))
 (defn- fresh-label [prefix] (str prefix (swap! gensym-counter inc)))
@@ -249,6 +268,17 @@
     (if (or (contains? scheme-reserved s) (contains? bare-native-names s)) (str "_" s) s)))
 
 (declare emit)
+(declare emit*)
+;; Ops that pass tail position through to a child (the child can itself be a tail
+;; call): if/do carry it to their tail branch/last form, let/loop to their body,
+;; and invoke reads it to decide whether the call is tail. Every other op's
+;; children are non-tail, so `emit` clears *tail?* before dispatching them — that
+;; way a stray true can't leak into, say, a call sitting in a vector literal.
+(def ^:private tail-transparent-ops #{:if :do :let :loop :invoke})
+(defn emit [node]
+  (if (and *tail?* (not (tail-transparent-ops (:op node))))
+    (binding [*tail?* false] (emit* node))
+    (emit* node)))
 
 ;; A Chez string literal. Every char outside printable ASCII becomes a
 ;; codepoint hex escape \x<cp>; ; the named escapes (\n \t \r \" \\) match what
@@ -409,9 +439,10 @@
 ;; letfn lowers to a :let flagged :letrec (mutually-recursive named local fns):
 ;; Scheme `letrec*` binds them so each sees its siblings. A plain let uses let*.
 (defn- emit-let [node]
-  (let [kw (if (:letrec node) "letrec*" "let*")]
-    (str "(" kw " (" (str/join " " (map emit-binding (:bindings node))) ") "
-         (emit (:body node)) ")")))
+  (let [kw (if (:letrec node) "letrec*" "let*")
+        ;; bindings are non-tail; the body inherits the let's tail position
+        binds (binding [*tail?* false] (str/join " " (mapv emit-binding (:bindings node))))]
+    (str "(" kw " (" binds ") " (emit (:body node)) ")")))
 
 (defn- emit-loop [node]
   (let [label (fresh-label "loop")
@@ -419,9 +450,10 @@
         names (map #(munge-name (nth % 0)) pairs)
         ;; inits evaluate in the OUTER scope (recur-target unchanged) and, like
         ;; Clojure loop/let, SEQUENTIALLY — wrap a let* around the named let.
-        inits (map #(emit (nth % 1)) pairs)
+        inits (binding [*tail?* false] (mapv #(emit (nth % 1)) pairs))
         seq-bs (str/join " " (map (fn [n i] (str "(" n " " i ")")) names inits))
         rebinds (str/join " " (map (fn [n] (str "(" n " " n ")")) names))
+        ;; the loop body inherits the loop's tail position
         body (binding [*recur-target* label] (emit (:body node)))]
     (str "(let* (" seq-bs ") (let " label " (" rebinds ") " body "))")))
 
@@ -482,7 +514,11 @@
         params (map munge-name orig)
         restp (when-let [r (:rest a)] (munge-name r))
         label (fresh-label "fnrec")
-        body (binding [*recur-target* label] (emit (:body a)))
+        ret (:ret-nhint a)
+        ;; the body is the fn's tail position — UNLESS a ^double/^long return hint
+        ;; wraps it in a coercion below, which puts the body back in non-tail.
+        body-tail? (not (or (= ret :double) (= ret :long)))
+        body (binding [*recur-target* label *tail?* body-tail?] (emit (:body a)))
         paramlist (cond
                     (and restp (empty? params)) restp
                     restp (str "(" (str/join " " params) " . " restp ")")
@@ -507,6 +543,16 @@
         self (when-let [nm (:name node)] (munge-name nm))
         clauses (binding [*known-procs* (if self (conj *known-procs* self) *known-procs*)]
                   (mapv emit-arity-clause arities))
+        ;; trace mode: record this frame on entry (before the body), so a frame
+        ;; the body then tail-calls away is still in the ring at throw time. A
+        ;; `recur` re-enters via the named-let, not the lambda, so a tight loop
+        ;; records once, not per iteration.
+        clauses (if (and @trace-frames? self)
+                  (mapv (fn [c] [(nth c 0)
+                                 (str "(begin (jolt-trace-push! " (chez-str-lit self) ") "
+                                      (nth c 1) ")")])
+                        clauses)
+                  clauses)
         lambda (if (= 1 (count clauses))
                  (let [c (first clauses)] (str "(lambda " (nth c 0) " " (nth c 1) ")"))
                  (str "(case-lambda "
@@ -569,8 +615,31 @@
             (= (nth shape i) kw) i
             :else (recur (inc i))))))
 
+;; A plain Scheme application: (callee op ...).
+(defn- plain-call [callee operand-strs]
+  (str "(" callee (if (seq operand-strs) (str " " (str/join " " operand-strs)) "") ")"))
+;; A tail call in trace mode. Force-bind the operands to temps FIRST (so any
+;; operand whose own evaluation records a trace entry runs before our mark), THEN
+;; set the tail mark, THEN apply — the callee's entry prologue consumes the mark
+;; with nothing in between, so it can't be clobbered. Still a tail call: the let*'s
+;; last form is the application, so TCO is preserved.
+(defn- tail-marked-call [callee operand-strs]
+  (let [tmps (mapv (fn [_] (fresh-label "_tt$")) operand-strs)
+        binds (str/join " " (map (fn [t a] (str "(" t " " a ")")) tmps operand-strs))]
+    (str "(let* (" binds ") (jolt-trace-mark! #t) " (plain-call callee tmps) ")")))
+;; Emit a call, tail-marked when we're in tail position and tracing is on; a plain
+;; application otherwise. The mark is consumed by the callee's entry prologue —
+;; direct calls (:local known-proc, direct-link) always have one; a jolt-invoke
+;; call usually reaches one but not always (see the best-effort note in rt.ss).
+(defn- emit-call [tail? callee operand-strs]
+  (if (and @trace-frames? tail?)
+    (tail-marked-call callee operand-strs)
+    (plain-call callee operand-strs)))
+
 (defn- emit-invoke [node]
-  (let [fnode (:fn node)
+  (let [tail? *tail?*]           ; capture: children below emit non-tail
+   (binding [*tail?* false]
+    (let [fnode (:fn node)
         arg-nodes (:args node)
         args (mapv emit arg-nodes)
         nop (native-op fnode (count args))
@@ -582,8 +651,7 @@
         ;; order [callee & args] together when ordering is observable.
         invoke (fn []
                  (ordered-call (cons fnode arg-nodes) (cons (emit fnode) args)
-                               (fn [[f & as]]
-                                 (str "(jolt-invoke " f (if (seq as) (str " " (str/join " " as)) "") ")"))))]
+                               (fn [operands] (emit-call tail? "jolt-invoke" operands))))]
     (cond
       ;; devirtualized protocol call: the inference proved the receiver (arg 0) is
       ;; one record type, so resolve the impl by that static tag instead of routing
@@ -632,11 +700,16 @@
         (if idx
           (order-args (fn [as] (str "(jrec-field-at " (first as) " " idx " " (emit fnode) ")")))
           (order-args (fn [as] (str "(jolt-get " (first as) " " (emit fnode) (defstr as) ")")))))
-      ;; (coll k [default]) -> (jolt-get coll k [default]) — coll (fnode) is the
-      ;; callee, evaluated before the key/default args.
+      ;; (coll k [default]) -> lookup — coll (fnode) is the callee, evaluated
+      ;; before the key/default args. A VECTOR literal invokes as nth (a bad
+      ;; index throws, IPersistentVector.invoke); maps/sets invoke as get.
       (= kind :coll)
       (ordered-call (cons fnode arg-nodes) (cons (emit fnode) args)
-                    (fn [[c & as]] (str "(jolt-get " c " " (str/join " " as) ")")))
+                    (fn [[c & as]]
+                      (str (if (and (= :vector (:op fnode)) (= 1 (count as)))
+                             "(jolt-nth "
+                             "(jolt-get ")
+                           c " " (str/join " " as) ")")))
       (and (stdlib-var? fnode) (not (deref prelude-mode?)))
       (throw (ex-info (str "emit: unsupported stdlib fn `" (:ns fnode) "/" (:name fnode)
                            "` (no core on Chez yet)") {}))
@@ -653,8 +726,7 @@
       ;; holds an arbitrary IFn -> dynamic dispatch.
       (= :local (:op fnode))
       (if (*known-procs* (munge-name (:name fnode)))
-        (order-args (fn [as] (str "(" (munge-name (:name fnode))
-                                  (if (seq as) (str " " (str/join " " as)) "") ")")))
+        (order-args (fn [as] (emit-call tail? (munge-name (:name fnode)) as)))
         (invoke))
       ;; closed-world direct call: the callee var is an app fn def already emitted
       ;; with a Scheme binding — apply it directly, no var lookup, no jolt-invoke.
@@ -663,8 +735,7 @@
       ;; below (which still uses the direct binding as the invoke target).
       (and (= :var (:op fnode)) (direct-linkable? (:ns fnode) (:name fnode))
            (direct-link-fn? (:ns fnode) (:name fnode)))
-      (order-args (fn [as] (str "(" (dl-name (:ns fnode) (:name fnode))
-                                (if (seq as) (str " " (str/join " " as)) "") ")")))
+      (order-args (fn [as] (emit-call tail? (dl-name (:ns fnode) (:name fnode)) as)))
       ;; a late-bound :var call head can hold a procedure OR a non-applicable
       ;; value the RT dispatches (multimethod, keyword/coll IFn) — route via
       ;; jolt-invoke (transparent for a procedure).
@@ -672,7 +743,7 @@
       (invoke)
       ;; a computed callee can yield ANY IFn — route through jolt-invoke.
       :else
-      (invoke))))
+      (invoke))))))
 
 ;; try/catch/finally. throw raises a Chez condition wrapping the jolt value
 ;; (jolt-throw = Scheme `raise` of a &jolt-throw condition); catch lowers to
@@ -719,7 +790,22 @@
        (returns-scheme-bool? (:body node) bools'))
      :else false)))
 
-(defn emit [node]
+;; In trace mode, a fn def also registers its source so the tail-frame history maps
+;; the recorded frame-name to "ns/name (file:line)" instead of a bare name. Keyed by
+;; the SAME munged name the entry push records (emit-fn's letrec self-binding = the
+;; fn's own name). Returns "" when off / not a positioned fn def, so trace-off output
+;; (seed mint, `jolt build`) is byte-identical. Direct-link builds already register
+;; via emit-def-cached; this covers the open-world eval path.
+(defn- trace-source-reg [node]
+  (let [init (:init node) pos (:pos node)]
+    (if (and @trace-frames? (= :fn (:op init)) (:name init) pos)
+      (str " (jolt-register-source! " (chez-str-lit (munge-name (:name init))) " "
+           (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) " "
+           (if (:file pos) (chez-str-lit (:file pos)) "jolt-nil") " "
+           (or (:line pos) 0) ")")
+      "")))
+
+(defn emit* [node]
   (case (:op node)
     :const (emit-const (:val node))
     :local (munge-name (:name node))
@@ -767,11 +853,14 @@
     :host-new (str "(host-new " (chez-str-lit (:class node))
                    (let [args (map emit (:args node))]
                      (if (empty? args) "" (str " " (str/join " " args)))) ")")
+    ;; the test is non-tail; then/else inherit the if's tail position
     :if (let [test (:test node)
-              t (if (returns-scheme-bool? test) (emit test)
-                    (str "(jolt-truthy? " (emit test) ")"))]
+              t (binding [*tail?* false]
+                  (if (returns-scheme-bool? test) (emit test)
+                      (str "(jolt-truthy? " (emit test) ")")))]
           (str "(if " t " " (emit (:then node)) " " (emit (:else node)) ")"))
-    :do (str "(begin " (str/join " " (map emit (:statements node)))
+    ;; non-last statements are non-tail; the ret inherits the do's tail position
+    :do (str "(begin " (binding [*tail?* false] (str/join " " (mapv emit (:statements node))))
              (if (empty? (:statements node)) "" " ") (emit (:ret node)) ")")
     :invoke (emit-invoke node)
     ;; collection literals -> rt constructors (collections.ss). Elements are
@@ -815,15 +904,17 @@
     :fn (emit-fn node)
     ;; (def name) with no init (declare): reserve the cell. A def with non-empty
     ;; reader metadata lowers to def-var-with-meta! (ported in a later increment).
-    :def (cond
-           (:no-init node)
-           (str "(declare-var! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) ")")
-           (jmeta-nonempty? (:meta node))
-           (str "(def-var-with-meta! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) " "
-                (emit-with-cells #(emit (:init node))) " " (emit-def-meta node) ")")
-           :else
-           (str "(def-var! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) " "
-                (emit-with-cells #(emit (:init node))) ")"))
+    :def (let [reg (trace-source-reg node)
+               d (cond
+                   (:no-init node)
+                   (str "(declare-var! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) ")")
+                   (jmeta-nonempty? (:meta node))
+                   (str "(def-var-with-meta! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) " "
+                        (emit-with-cells #(emit (:init node))) " " (emit-def-meta node) ")")
+                   :else
+                   (str "(def-var! " (chez-str-lit (:ns node)) " " (chez-str-lit (:name node)) " "
+                        (emit-with-cells #(emit (:init node))) ")"))]
+           (if (= reg "") d (str "(begin " d reg ")")))
     (throw (ex-info (str "emit: op not yet ported / unhandled: " (pr-str (:op node))) {}))))
 
 ;; ^:dynamic / ^:redef on a def opts it out of direct-linking: it stays redefinable,

jolt-core/jolt/deps.clj

@@ -66,6 +66,10 @@
       (if-let [root (:deps/root spec)] (str checkout "/" root) checkout))
     (:jolt/module spec)
     (do (warn "skipping janet dependency " coord " (:jolt/module is obsolete on Chez)") nil)
+    ;; jolt IS Clojure — a dependency on org.clojure/clojure is satisfied
+    ;; intrinsically, so skip it silently rather than warning about the (unusable)
+    ;; :mvn/version coordinate.
+    (= coord 'org.clojure/clojure) nil
     :else
     (do (warn "skipping unsupported coordinate " coord " " (pr-str spec)) nil)))
 

jolt-core/jolt/main.clj

@@ -8,6 +8,8 @@
 
 (defn- project-dir [] (or (jolt.host/getenv "JOLT_PWD") "."))
 
+(defn- version [] (jolt.host/jolt-version))
+
 (defn- current-platform []
   (let [os (str/lower-case (or (System/getProperty "os.name") ""))]
     (cond (str/includes? os "mac") :darwin
@@ -145,7 +147,10 @@
   ;; loaded — same context a run gets, so (require '[some.lib]) works in the REPL.
   (try (apply-project! (deps/resolve-project (project-dir)))
        (catch :default _ nil))
-  (println ";; jolt repl — :repl/quit or ^D to exit")
+  ;; REPL-driven development: trace by default so an uncaught error in evaluated
+  ;; code shows a tail-frame backtrace, no JOLT_TRACE needed (JOLT_TRACE=0 opts out).
+  (jolt.host/enable-trace!)
+  (println (str ";; jolt " (version) " repl — :repl/quit or ^D to exit"))
   (loop []
     (let [form (repl-read-form)]
       (when form
@@ -158,7 +163,9 @@
                  (catch :default e
                    (println "error:" (or (ex-message e)
                                          (try ((resolve 'jolt.host/condition-message) e) (catch :default _ nil))
-                                         (pr-str e)))))
+                                         (pr-str e)))
+                   (when-let [bt (jolt.host/backtrace-string)]
+                     (print bt))))
             (recur)))))))
 
 ;; A deps.edn :tasks entry: a string is a shell command; a map is {:main-opts …}.
@@ -294,7 +301,9 @@
         (when stop (stop))))))
 
 (defn- usage []
+  (println (str "jolt " (version)))
   (println "usage: jolt <command> [args]")
+  (println "  -e EXPR                evaluate EXPR and print the result")
   (println "  run -m NS [args]       resolve deps.edn, load NS, call its -main")
   (println "  run FILE               load a Clojure file")
   (println "  build -m NS [-o OUT] [--opt|--dev] [--direct-link] [--tree-shake] [--dynamic]  compile a standalone binary")
@@ -304,6 +313,7 @@
   (println "  --nrepl-server [port]  start an nREPL server (default 7888) for editors")
   (println "  path                   print the resolved source roots")
   (println "  <task>                 run a deps.edn :tasks entry")
+  (println "  --version              print the jolt version")
   (println "  --help                 print this message"))
 
 (defn -main [& args]
@@ -312,6 +322,7 @@
       (nil? cmd)                  (usage)
       (= cmd "--help")            (usage)
       (= cmd "-h")                (usage)
+      (#{"--version" "-V"} cmd)   (println (str "jolt " (version)))
       (= cmd "run")               (cmd-run more)
       (= cmd "repl")              (repl)
       (= cmd "--nrepl-server")    (nrepl more)

jolt-core/jolt/nrepl.clj

@@ -21,25 +21,66 @@
             [jolt.ffi :as ffi]))
 
 ;; --- sockets (loopback server) ---------------------------------------------
-;; Load libc (the running process's symbols) BEFORE the foreign-fn bindings below
-;; — defcfn resolves the C entry point when the def is evaluated (at ns load), so
-;; the socket symbols must already be available.
-(ffi/load-library)
+(def ^:private os-name
+  (str/lower-case (or (System/getProperty "os.name") "")))
+(def ^:private macos?   (str/includes? os-name "mac"))
+(def ^:private windows? (str/includes? os-name "win"))
+
+;; Load the library that provides the socket symbols BEFORE the foreign-fn
+;; bindings below — defcfn resolves the C entry point when the def is evaluated
+;; (at ns load), so the symbols must already be available. POSIX: the running
+;; process's own libc symbols. Windows: the Winsock DLL (ws2_32), whose symbols
+;; are NOT in joltc.exe's export table even though it's linked in — without this
+;; explicit load, (ffi/defcfn c-socket "socket" ...) fails at load with
+;; "no entry for socket".
+(if windows?
+  (ffi/load-library "ws2_32.dll")
+  (ffi/load-library))
+
+;; A socket is an int fd on POSIX; on Win64 it's a SOCKET (uintptr_t) handle, but
+;; those are small kernel handle values that round-trip through :int, and the
+;; INVALID_SOCKET error sentinel (~0) reads back as -1 — so the fd checks below
+;; work unchanged on both.
 (ffi/defcfn c-socket     "socket"     [:int :int :int] :int)
 (ffi/defcfn c-bind       "bind"       [:int :pointer :int] :int)
 (ffi/defcfn c-listen     "listen"     [:int :int] :int)
 (ffi/defcfn c-setsockopt "setsockopt" [:int :int :int :pointer :int] :int)
-  (ffi/defcfn c-accept     "accept"     [:int :pointer :pointer] :int :blocking)
-  (ffi/defcfn c-recv       "recv"       [:int :pointer :size_t :int] :ssize_t :blocking)
-  (ffi/defcfn c-send       "send"       [:int :pointer :size_t :int] :ssize_t :blocking)
-(ffi/defcfn c-close      "close"      [:int] :int)
+(ffi/defcfn c-accept     "accept"     [:int :pointer :pointer] :int :blocking)
+
+;; recv/send and the socket-close call differ by platform. Winsock's recv/send
+;; take an int length and return int (not ssize_t), and a socket is closed with
+;; closesocket, not close. A symbol that exists on only one OS (closesocket on
+;; Windows, close on POSIX) can only be bound there, so these live in the taken
+;; platform branch — jolt interns the vars from both branches at analysis time,
+;; so later references resolve either way.
+(if windows?
+  (do
+    (ffi/defcfn c-recv  "recv"        [:int :pointer :int :int] :int :blocking)
+    (ffi/defcfn c-send  "send"        [:int :pointer :int :int] :int :blocking)
+    (ffi/defcfn c-close "closesocket" [:int] :int)
+    ;; Winsock must be initialized once per process before any socket call.
+    (ffi/defcfn c-wsastartup "WSAStartup" [:int :pointer] :int))
+  (do
+    (ffi/defcfn c-recv  "recv"  [:int :pointer :size_t :int] :ssize_t :blocking)
+    (ffi/defcfn c-send  "send"  [:int :pointer :size_t :int] :ssize_t :blocking)
+    (ffi/defcfn c-close "close" [:int] :int)))
 
 (def ^:private AF-INET 2)
 (def ^:private SOCK-STREAM 1)
-(def ^:private macos?
-  (str/includes? (str/lower-case (or (System/getProperty "os.name") "")) "mac"))
-(def ^:private sol-socket (if macos? 0xffff 1))
-(def ^:private so-reuse   (if macos? 4 2))
+;; SOL_SOCKET / SO_REUSEADDR: 0xffff / 4 on macOS and Windows, 1 / 2 on Linux.
+(def ^:private sol-socket (if (or macos? windows?) 0xffff 1))
+(def ^:private so-reuse   (if (or macos? windows?) 4 2))
+
+;; Initialize Winsock (a no-op off Windows). WSAStartup is refcounted and must
+;; precede any socket call; WSADATA is ~408 bytes on x64, so 512 is ample.
+(defn- ensure-winsock! []
+  (when windows?
+    (let [wsadata (ffi/alloc 512)]
+      (try
+        (let [r (c-wsastartup 0x0202 wsadata)]
+          (when-not (zero? r)
+            (throw (ex-info (str "WSAStartup failed: " r) {}))))
+        (finally (ffi/free wsadata))))))
 
 (defn- make-sockaddr [port]
   (let [sa (ffi/alloc 16)]
@@ -53,7 +94,7 @@
     sa))
 
 (defn- listen-socket [port]
-  (ffi/load-library)                                         ; libc process symbols
+  (ensure-winsock!)                                          ; no-op off Windows
   (let [fd (c-socket AF-INET SOCK-STREAM 0)]
     (when (neg? fd) (throw (ex-info "socket() failed" {})))
     (let [opt (ffi/alloc 4)] (ffi/write opt :int 0 1) (c-setsockopt fd sol-socket so-reuse opt 4) (ffi/free opt))
@@ -147,7 +188,10 @@
               (try (when (and ns-str (not (str/blank? ns-str)) (find-ns (symbol ns-str)))
                      (in-ns (symbol ns-str)))
                    (reset! result (load-string code))
-                   (catch :default e (reset! err (err-msg e)))))]
+                   (catch :default e
+                     (reset! err (str (err-msg e)
+                                      (when-let [bt (jolt.host/backtrace-string)]
+                                        (str "\n" bt)))))))]
     {:value (when (nil? @err) (pr-str @result))
      :out out
      :ns (str (ns-name *ns*))
@@ -236,11 +280,17 @@
   no-op."
   ([port] (start port nil))
   ([port middleware]
+   ;; An nREPL session is REPL-driven development: trace by default so an uncaught
+   ;; error in code evaluated over the connection shows a tail-frame backtrace, with
+   ;; no JOLT_TRACE needed. Covers both `--nrepl-server` and an app that starts its
+   ;; own server under `-M:run` (reload a namespace to trace already-loaded code).
+   (jolt.host/enable-trace!)
    (let [handler (build-handler (resolve-middleware (or middleware [])))
          fd (listen-socket port)                  ; throws on bind/listen failure
          stopped (atom false)]
      (try (spit ".nrepl-port" (str port)) (catch :default _ nil))
-     (println (str "nREPL server started on port " port " (127.0.0.1) — .nrepl-port written"))
+     (println (str "jolt " (jolt.host/jolt-version) " nREPL server started on port "
+                   port " (127.0.0.1) — .nrepl-port written"))
      (when (seq middleware) (println (str ";; middleware: " (str/join " " middleware))))
      (println ";; connect your editor; ^C to stop")
       (future

jolt-core/jolt/passes/numeric.clj

@@ -183,7 +183,12 @@
             ls (lng-spec nm n)
             bs (bd-spec nm n)]
         (cond
-          (and ds (ok? :double :double))
+          (and ds (ok? :double :double)
+               ;; min/max return the ORIGINAL operand (Numbers.min: an integer
+               ;; literal stays exact), so an int-literal operand blocks the
+               ;; flonum lowering there — flmin would coerce it.
+               (or (not (contains? #{"min" "max"} nm))
+                   (every? (fn [c] (= c :double)) cls)))
           ;; coerce integer-literal operands to flonum so fl-ops never see an exact int.
           (let [args' (mapv (fn [nd] (if (int-lit? nd) (assoc nd :val (double (get nd :val))) nd))
                             argnodes)]

stdlib/clojure/edn.clj

@@ -16,7 +16,15 @@
     ;; Reader FORMS are detected by :jolt/type tag, never by map? — strict map?
     ;; (correctly) excludes tagged structs, so the old (and (map? x) ...) guard
     ;; would skip them.
-    (= :jolt/set (get x :jolt/type)) (with-meta (set (map (fn [v] (edn->value opts v)) (get x :value))) (edn->value opts (meta x)))
+    (= :jolt/set (get x :jolt/type))
+      (let [vs (map (fn [v] (edn->value opts v)) (get x :value))
+            st (set vs)]
+        ;; duplicate literal elements are invalid edn
+        (when (< (count st) (count vs))
+          (throw (new IllegalArgumentException
+                      (str "Duplicate key: " (pr-str (some (fn [[k n]] (when (< 1 n) k))
+                                                           (frequencies vs)))))))
+        (with-meta st (edn->value opts (meta x))))
     ;; Tagged elements: a reader from the :readers opt wins, then the built-in
     ;; data readers (#uuid/#inst + registered); an unknown tag falls to the
     ;; :default opt fn (called with tag and value, as in Clojure) or throws.
@@ -30,6 +38,9 @@
             custom (get (get opts :readers) tag-sym)]
         (cond
           custom (custom v)
+          ;; the built-in edn tags win over :default (a :readers entry can
+          ;; override them; an unknown-tag :default never sees #inst/#uuid)
+          (contains? #{'inst 'uuid 'bigdec} tag-sym) (__read-tagged tag v)
           ;; Clojure calls :default with the tag as a SYMBOL and the value.
           (get opts :default) ((get opts :default) tag-sym v)
           :else (__read-tagged tag v)))
@@ -39,25 +50,30 @@
     ;; a constructed set: recurse into its elements too, so a tagged literal
     ;; inside #{…} gets the :readers/:default treatment (aero's #ref in a set).
     (set? x) (with-meta (set (map (fn [v] (edn->value opts v)) x)) (edn->value opts (meta x)))
-    (seq? x) (with-meta (map (fn [v] (edn->value opts v)) x) (edn->value opts (meta x)))
+    ;; edn lists are lists (list? holds), not lazy seqs
+    (seq? x) (with-meta (apply list (map (fn [v] (edn->value opts v)) x)) (edn->value opts (meta x)))
     :else x))
 
 ;; Private helper, NOT named read-string: an unqualified (read-string …) call
 ;; dispatches the core read-string SPECIAL FORM (by name, regardless of ns), so
 ;; the 1-arity can't delegate to the 2-arity through that name.
 (defn- read-edn [opts s]
-  (if (or (nil? s) (cstr/blank? s))
-    (get opts :eof nil)
-    ;; read the RAW form (tagged/set literals stay forms) so edn->value applies
-    ;; every #tag through :readers/:default — read-string would build the built-in
-    ;; #inst/#uuid eagerly, ignoring an override and failing on a non-string form.
-    (edn->value opts (__read-form-raw s))))
+  ;; the strict edn seam: no auto-resolved keywords, invalid tokens throw, and
+  ;; each #_ discard is validated through the same :readers/:default pipeline.
+  ;; EOF (blank/comment-only/nil input) honors :eof; an opts map WITHOUT :eof
+  ;; makes end-of-input an error, like the reference.
+  (let [v (__read-form-edn s (fn [form] (edn->value opts form) nil))]
+    (if (= v :jolt/reader-eof)
+      (if (contains? opts :eof)
+        (get opts :eof)
+        (throw (ex-info "EOF while reading" {})))
+      (edn->value opts v))))
 
 (defn read-string
-  "Reads one object from the string s. Returns the :eof option value (default
-  nil) for nil or blank input. opts is an options map; :eof sets the value
-  returned at end of input."
-  ([s] (read-edn {} s))
+  "Reads one object from the string s. The no-opts arity returns nil at end of
+  input; with an opts map, :eof sets the value returned at end of input and its
+  absence makes end-of-input an error."
+  ([s] (read-edn {:eof nil} s))
   ([opts s] (read-edn opts s)))
 
 (defn- drain-reader

stdlib/clojure/string.clj

@@ -6,28 +6,32 @@
   (if (nil? s) true
     (= 0 (count (str-trim s)))))
 
+;; The case fns and the searches take any Object s through its toString, like
+;; the reference ((upper-case :kw) is ":KW", (capitalize 1) is "1"); nil throws
+;; like calling a method on null.
+(defn- to-str [s]
+  (if (nil? s)
+    (throw (new NullPointerException "s"))
+    (.toString s)))
 (defn capitalize
-  
   [s]
-  (if (< 1 (count s))
-    (str (str-upper (subs s 0 1))
-         (str-lower (subs s 1)))
-    (str-upper s)))
+  (let [s (to-str s)]
+    (if (< 1 (count s))
+      (str (str-upper (subs s 0 1))
+           (str-lower (subs s 1)))
+      (str-upper s))))
 
 (defn lower-case
-  
   [s]
-  (str-lower s))
+  (str-lower (to-str s)))
 
 (defn upper-case
-  
   [s]
-  (str-upper s))
+  (str-upper (to-str s)))
 
 (defn includes?
-  
   [s substr]
-  (not (nil? (str-find substr s))))
+  (not (nil? (str-find substr (to-str s)))))
 
 (defn join
   
@@ -36,11 +40,11 @@
 
 (defn replace
   [s match replacement]
-  (str-replace-all match replacement s))
+  (str-replace-all match replacement (to-str s)))
 
 (defn replace-first
   [s match replacement]
-  (str-replace match replacement s))
+  (str-replace match replacement (to-str s)))
 
 (defn reverse
   [s]
@@ -68,16 +72,18 @@
   (vec (str-split #"\r?\n" s)))
 
 (defn starts-with?
-  
   [s substr]
-  (let [slen (count s) slen2 (count substr)]
+  (when (nil? substr) (throw (new NullPointerException "substr")))
+  (let [s (to-str s)
+        slen (count s) slen2 (count substr)]
     (and (>= slen slen2)
          (= (subs s 0 slen2) substr))))
 
 (defn ends-with?
-  
   [s substr]
-  (let [slen (count s) slen2 (count substr)]
+  (when (nil? substr) (throw (new NullPointerException "substr")))
+  (let [s (to-str s)
+        slen (count s) slen2 (count substr)]
     (and (>= slen slen2)
          (= (subs s (- slen slen2)) substr))))
 
@@ -97,8 +103,8 @@
   (str-trimr s))
 
 (defn escape
-  
   [s cmap]
+  (when (nil? s) (throw (new NullPointerException "s")))
   (apply str
     (map (fn [ch]
            (if-let [rep (cmap ch)] rep (str ch)))
@@ -107,9 +113,9 @@
 (defn index-of
   "0-based index of the first occurrence of value in s, or nil."
   ([s value]
-   (str-find value s))
+   (str-find value (to-str s)))
   ([s value from]
-   (let [idx (str-find value (subs s from))]
+   (let [idx (str-find value (subs (to-str s) from))]
      (when idx (+ from idx)))))
 
 (defn last-index-of

test/chez/README.md

@@ -7,7 +7,7 @@ test` from the repo root.
 
 ## The spec corpus
 
-`corpus.edn` is the contract: ~2920 rows `{:suite :label :expected :actual}`, with
+`corpus.edn` is the contract: ~3570 rows `{:suite :label :expected :actual :portability}`, with
 `:expected` sourced from reference JVM Clojure by `test/conformance/regen-corpus.clj`.
 It is frozen (the canonical source) — add or change cases here, then re-source the
 answers with `regen-corpus.clj` and re-certify with `test/conformance/certify.clj`.
@@ -22,7 +22,7 @@ answers with `regen-corpus.clj` and re-certify with `test/conformance/certify.cl
 
       chez --script host/chez/run-corpus.ss
       JOLT_CORPUS_LIMIT=200 …            # every-Nth stride, fast iteration
-      JOLT_CHEZ_ZJ_FLOOR=N …            # override the floor (default 2678)
+      JOLT_CHEZ_ZJ_FLOOR=N …            # override the floor (see run-corpus.ss)
 
 - `run-unit.ss` — host-specific unit cases (`test/chez/unit.edn`) that aren't in the
   JVM-portable corpus: dot-forms, java statics, io, reader, walk, vars/namespaces,

test/chez/cts-known-failures.txt

@@ -1,87 +1,32 @@
 # clojure-test-suite known failures: <namespace> <fail> <error>
 # The gate fails on any per-namespace change, worse OR better; regenerate
 # with: JOLT_CTS_WRITE_BASELINE=1 host/chez/cts.sh
-clojure.core-test.abs 1 1
-clojure.core-test.add-watch 0 3
-clojure.core-test.ancestors 9 0
-clojure.core-test.atom 14 0
+clojure.core-test.abs 1 0
+clojure.core-test.add-watch 0 1
 clojure.core-test.bigint 6 0
 clojure.core-test.bit-set 1 0
-clojure.core-test.boolean-qmark 0 3
-clojure.core-test.byte 7 5
-clojure.core-test.char 1 0
-clojure.core-test.compare 1 0
-clojure.core-test.conj 1 0
-clojure.core-test.contains-qmark 3 0
-clojure.core-test.counted-qmark 1 0
 clojure.core-test.dec 1 0
-clojure.core-test.denominator 0 3
-clojure.core-test.derive 21 0
-clojure.core-test.descendants 4 0
-clojure.core-test.double 0 4
 clojure.core-test.double-qmark 3 0
-clojure.core-test.empty 1 0
 clojure.core-test.eq 2 0
-clojure.core-test.eval 0 3
-clojure.core-test.even-qmark 1 0
-clojure.core-test.float 4 4
-clojure.core-test.get 0 1
-clojure.core-test.ifn-qmark 2 0
+clojure.core-test.float 1 0
 clojure.core-test.inc 1 0
-clojure.core-test.int 4 5
 clojure.core-test.int-qmark 3 0
-clojure.core-test.intern 2 0
-clojure.core-test.keys 0 4
-clojure.core-test.lazy-seq 3 0
-clojure.core-test.long 2 5
-clojure.core-test.max 3 1
-clojure.core-test.min 3 1
+clojure.core-test.lazy-seq 1 2
 clojure.core-test.minus 2 0
-clojure.core-test.mod 12 34
+clojure.core-test.mod 18 0
 clojure.core-test.neg-int-qmark 1 0
 clojure.core-test.not-eq 3 0
-clojure.core-test.nth 0 1
-clojure.core-test.num 2 1
-clojure.core-test.number-qmark 3 0
-clojure.core-test.numerator 0 3
-clojure.core-test.odd-qmark 1 0
-clojure.core-test.parents 10 0
+clojure.core-test.num 2 0
 clojure.core-test.parse-uuid 3 0
-clojure.core-test.peek 2 0
+clojure.core-test.peek 1 0
 clojure.core-test.plus 11 0
 clojure.core-test.plus-squote 11 0
-clojure.core-test.pop 0 1
 clojure.core-test.pos-int-qmark 1 0
-clojure.core-test.quot 12 23
-clojure.core-test.rand-nth 0 1
-clojure.core-test.rational-qmark 3 0
-clojure.core-test.rationalize 10 0
-clojure.core-test.realized-qmark 3 0
-clojure.core-test.reduce 0 1
-clojure.core-test.rem 12 22
+clojure.core-test.quot 25 0
+clojure.core-test.realized-qmark 1 0
+clojure.core-test.rem 16 0
 clojure.core-test.remove-watch 0 1
-clojure.core-test.run-bang 1 0
-clojure.core-test.select-keys 2 0
-clojure.core-test.seqable-qmark 1 0
-clojure.core-test.short 7 5
-clojure.core-test.shuffle 1 0
-clojure.core-test.slash 2 22
-clojure.core-test.some-fn 3 0
-clojure.core-test.sort-by 2 0
-clojure.core-test.special-symbol-qmark 4 0
-clojure.core-test.star 22 0
-clojure.core-test.star-squote 19 0
-clojure.core-test.transient 23 0
-clojure.core-test.underive 7 0
-clojure.core-test.update 1 0
-clojure.core-test.vals 0 3
+clojure.core-test.star 13 0
+clojure.core-test.star-squote 13 0
+clojure.core-test.transient 4 0
 clojure.core-test.vec 1 0
-clojure.core-test.when-let 1 0
-clojure.core-test.with-precision 17 0
-clojure.edn-test.read-string 46 5
-clojure.string-test.capitalize 0 4
-clojure.string-test.ends-with-qmark 1 4
-clojure.string-test.escape 1 0
-clojure.string-test.lower-case 0 4
-clojure.string-test.starts-with-qmark 1 10
-clojure.string-test.upper-case 0 4

test/chez/inline-test.ss

@@ -36,7 +36,7 @@
 (ev "(def add1 (fn* ([x] (+ x 1))))")
 (let ((e (emitf "u" "(fn* ([y] (add1 y)))")))
   (ok "plain fn is inlined (call to add1 gone)" (not (has? e "add1")))
-  (ok "inlined body present (+ ... 1)" (has? e "(+")))
+  (ok "inlined body present (jolt-n+ ... 1)" (has? e "(jolt-n+")))
 (ok "inlined plain fn runtime: (add1 41) = 42" (= 42 (jnum->exact (ev "((fn* ([y] (add1 y))) 41)"))))
 
 ;; a ^double fn: body fl-ops fire after inlining, and the call is gone.

test/chez/unit.edn

@@ -576,4 +576,26 @@
   {:suite "deftype-method" :expr "(do (defprotocol P (m [_ o])) (defrecord R [n] P (m [_ _] n)) (m (->R 5) :x))" :expected "5"}
   {:suite "deftype-method" :expr "(do (defprotocol P2 (m2 [_ o])) (deftype T [n] P2 (m2 [_ _] n)) (m2 (->T 7) :x))" :expected "7"}
   {:suite "protocol-host" :expr "(do (defprotocol Q (e [_])) (extend-protocol Q clojure.lang.Var (e [_] :var)) [(satisfies? Q (var map)) (e (var map))])" :expected "[true :var]"}
+
+  ;; Clojure 1.13 (1.13.0-alpha1) parity. Ahead of the JVM 1.12.5 the corpus
+  ;; certifies against, so these live here rather than as certified corpus rows.
+  {:suite "clj-1.13 req!" :expr "(req! {:a 1} :a)" :expected "1"}
+  {:suite "clj-1.13 req!" :expr "(req! [10 20 30] 1)" :expected "20"}
+  {:suite "clj-1.13 req!" :expr "(nil? (req! {:a nil} :a))" :expected "true"}
+  {:suite "clj-1.13 req!" :expr "(req! {:a 1} :b)" :expected :throws}
+  {:suite "clj-1.13 amp-binding" :expr "(let [& 42] &)" :expected :throws}
+  {:suite "clj-1.13 amp-binding" :expr "(loop [& 42] &)" :expected :throws}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:keys! [a b]} {:a 1 :b 2}] [a b])" :expected "[1 2]"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:keys! [a b]} {:a 1}] [a b])" :expected :throws}
+  {:suite "clj-1.13 checked-keys" :expr "(nil? (let [{:keys! [a]} {:a nil}] a))" :expected "true"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:strs! [a]} {\"a\" 5}] a)" :expected "5"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:keys! [a & b]} {:a 1 :b 2}] a)" :expected "1"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:keys! [a & b]} {:a 1}] a)" :expected :throws}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:keys [a & b]} {:a 1 :b 2}] a)" :expected "1"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:foo/keys! [a]} {:foo/a 7}] a)" :expected "7"}
+  {:suite "clj-1.13 checked-keys" :expr "(let [{:foo/keys! [a]} {}] a)" :expected :throws}
+  {:suite "clj-1.13 array-map-64" :expr "(keys {:a 1 :b 2 :c 3 :d 4 :e 5 :f 6 :g 7 :h 8 :i 9 :j 10})" :expected "(:a :b :c :d :e :f :g :h :i :j)"}
+  {:suite "clj-1.13 array-map-64" :expr "(= (map (fn [i] (keyword (str \"k\" i))) (range 20)) (keys (into {} (map (fn [i] [(keyword (str \"k\" i)) i]) (range 20)))))" :expected "true"}
+  {:suite "clj-1.13 array-map-64" :expr "(= (map (fn [i] (keyword (str \"k\" i))) (range 64)) (keys (reduce (fn [m i] (assoc m (keyword (str \"k\" i)) i)) {} (range 64))))" :expected "true"}
+  {:suite "clj-1.13 array-map-64" :expr "(= (map (fn [i] (keyword (str \"k\" i))) (range 65)) (keys (into {} (map (fn [i] [(keyword (str \"k\" i)) i]) (range 65)))))" :expected "false"}
 ]

test/conformance/SPEC.md

@@ -10,7 +10,7 @@ read one data file, run each case, compare, report.
 
 | File | Role | Generated by |
 |------|------|--------------|
-| `test/chez/corpus.edn` | **The spec.** ~2900 cases of `{:suite :label :expected :actual}`, `:expected` **sourced from reference JVM Clojure**. | `test/conformance/regen-corpus.clj` |
+| `test/chez/corpus.edn` | **The spec.** ~3570 cases of `{:suite :label :expected :actual :portability}`, `:expected` **sourced from reference JVM Clojure**. | `test/conformance/regen-corpus.clj` |
 | `test/conformance/profile.edn` | Per-case **feature classification** — which non-portable cases need which host capability. | `certify.clj --profile` |
 | `test/conformance/known-divergences.edn` | The few rows whose JVM value is an opaque host object that can't round-trip to readable source (Java arrays/transients/atoms/beans/proxies print as `#object[..@addr]`), so the corpus keeps jolt's value. | `regen-corpus.clj` leftovers, hand-checked |
 | `test/conformance/regen-corpus.clj` | Sources every `:expected` from reference **JVM Clojure** in one process. | — |
@@ -24,11 +24,17 @@ the canonical, frozen contract**: it is what every runtime consumes, what
 ## Row schema
 
 ```edn
-{:suite    "numbers / arithmetic"      ; grouping; "<suite> :: <label>" is the case id
- :label    "integer add"               ; unique within a suite
- :actual   "(+ 1 2)"                    ; Clojure source to evaluate
- :expected "3"}                         ; Clojure source whose value it must equal,
+{:suite       "numbers / arithmetic"   ; grouping; "<suite> :: <label>" is the case id
+ :label       "integer add"            ; unique within a suite
+ :actual      "(+ 1 2)"                 ; Clojure source to evaluate
+ :expected    "3"                       ; Clojure source whose value it must equal,
                                         ; or the keyword :throws
+ :portability :common}                  ; :common = portable Clojure any dialect
+                                        ; must satisfy; :jvm = exercises host
+                                        ; interop (java.*/clojure.lang.* classes,
+                                        ; dot forms, ctors, statics, arrays,
+                                        ; proxy/bean) — skip on a non-JVM-shaped
+                                        ; dialect
 ```
 
 - `[:suite :label]` is the **canonical, unique case id** (the generator
@@ -48,8 +54,8 @@ the canonical, frozen contract**: it is what every runtime consumes, what
 Historically every `:expected` was hand-written. `certify.clj` removes that
 weakness: it evaluates every `:actual` (and `:expected`) on **JVM Clojure** in a
 fresh `user` namespace and checks jolt's `:expected` against what real Clojure
-produces. Of ~2740 vanilla-certifiable rows, **>2730 match reference Clojure
-exactly**. The rest are classified (see below) — none are silently wrong.
+produces. Of ~3400 vanilla-certifiable rows, **all but ~26 allowlisted rows
+match reference Clojure exactly**. The rest are classified (see below) — none are silently wrong.
 
 ```sh
 clojure -M test/conformance/certify.clj                                  # gate
@@ -127,10 +133,49 @@ arithmetic, `=`, and `hash` behave exactly as the JVM — but report `Long`, not
 `Byte`/`Short`/`Integer`, so `(class (byte 5))` and `(instance? Byte (byte 5))`
 diverge. This is substrate-inherent: a Chez fixnum is an immediate `identical?`
 to the plain integer (nothing to tag, and numbers carry no metadata), so the only
-faithful representation is a boxed type — which would crash raw compiled `(+ …)`
-(arithmetic emits a bare Chez `+`) or force every `+`/`-`/`*` through an
-unwrapping dispatcher, de-optimizing all arithmetic. Same shape as the accepted
-BigInt-vs-Long unification.
+faithful representation is a boxed type — which would crash the compiled
+arithmetic fast path (both operands Chez numbers → the raw Chez op) or force
+every `+`/`-`/`*` through an unwrapping dispatcher, de-optimizing all
+arithmetic. Same shape as the accepted BigInt-vs-Long unification.
+
+The cast RANGE contract is full parity (corpus `casts / *`): `byte`/`short`/
+`int`/`long`/`char` range-check like `RT.byteCast` — an out-of-range value is
+IllegalArgumentException "Value out of range for byte: 128". A double operand
+range-checks ITSELF before truncating (`(byte 1.1)` is `1`, `(byte 127.000001)`
+throws), NaN casts to 0, ratios and bigdecs truncate, a non-number is
+ClassCastException. `float` range-checks against Float/MAX_VALUE. The
+`unchecked-*` casts wrap and sign-fold like the JVM primitive conversions
+(`(unchecked-byte 200)` is `-56`; a double saturates instead of wrapping).
+What jolt does NOT model is a distinct single-float type: `(float x)` keeps
+the double VALUE, so a double below Float/MIN_VALUE stays nonzero and float
+rounding does not occur (the accepted no-single-float residue, baselined with
+`:integer-box-model`'s class residue).
+
+## Number operations
+
+Binary arithmetic and comparisons follow the JVM's `Numbers.ops(x, y)` category
+dispatch. Every position (call, value, higher-order) funnels a binary op through
+one seam (`host/chez/seq.ss`): operands inside Chez's tower take the native op
+with the JVM contagion rules patched in; an operand outside it (BigDecimal)
+falls to a slow hook the numeric shim extends (`host/chez/java/bigdec.ss`); a
+non-numeric operand throws `ClassCastException`. The rules the corpus pins
+(`numbers / ops dispatch`, `numbers / with-precision`, `numbers / rationalize`):
+
+- A double operand wins: `(* 1.0 0)` is `0.0` (Chez's exact-zero shortcut must
+  not leak), `(* ##Inf 0)` is `##NaN`, `(+ 1.5M 2.0)` is `3.5`.
+- Division: an exact zero divisor throws `ArithmeticException`; a double zero
+  divisor yields `##Inf`/`##-Inf`/`##NaN`. `(/ 1M 3M)` with no bound
+  `*math-context*` throws (non-terminating); under `with-precision` it rounds.
+- `quot`/`rem`/`mod` cover the full tower (ratios truncate; doubles keep double;
+  `mod` takes the divisor's sign; zero divisor throws in both worlds).
+- `min`/`max` return the *original* operand (`(min 1 2.0)` is `1`, exact); a
+  `##NaN` operand wins.
+- `with-precision` binds `*math-context*`; BigDecimal results round to the
+  precision with the `java.math.RoundingMode` semantics (default `HALF_UP`,
+  `UNNECESSARY` throws).
+- `rationalize` routes a double through its shortest decimal print
+  (`BigDecimal.valueOf`), so `(rationalize 1.1)` is `11/10`, not the exact
+  binary expansion.
 
 ## Hosting jolt on a new runtime
 
@@ -166,3 +211,39 @@ corpus`.
   deliberate delta (classify it in `known-divergences.edn`).
 - **Refresh the profile**: re-run with `--profile test/conformance/profile.edn`.
 - **Re-floor the runtime gate** when parity rises (`host/chez/run-corpus.ss`).
+
+## clojure-test-suite baseline traceability
+
+Every residual entry in `test/chez/cts-known-failures.txt` traces to one
+documented model divergence — nothing in the baseline is an unexplained bug:
+
+- `:integer-box-model` (this file, above): every `big-int?`/`instance?
+  Byte…BigInt` class check, the overflow-throw rows (`(+ max-long 1)` is a
+  bignum, not ArithmeticException — abs/inc/dec/minus/plus/star/quot/rem/mod/
+  bit-set and the `+'`/`*'` promotion-identity namespaces), boxed-identity
+  rows (`(identical? (Boolean. "true") true)`, `(= x x)` on a boxed NaN — jolt
+  numbers are immediates, there is no box to distinguish), and `num`'s
+  primitive-overload reflection rows.
+- **no single float** (Narrow integer types, above): `(float Double/MIN_VALUE)`
+  keeps the double value instead of rounding to 0.0f; `(double? (float x))`
+  is true.
+- **RFC 0003 transients**: `(transient sorted/list/lazy-seq)` succeeds through
+  the copy-on-write fallback (a deliberate superset; non-collections now throw
+  like the JVM), and double-transient is idempotent rather than throwing.
+- `:seq-type-model`/`:chunking-model` (Seq semantics, above): `realized?` on
+  the rest of a realized chain (a plain seq cell on jolt, a cached LazySeq on
+  the JVM), `p/lazy-seq?` on forced rest chains, and chunk-granularity
+  realization counts (lazy-seq namespace).
+- **stm-refs** (`coverage.md`): the `(ref …)`/`dosync` sections of the watch
+  namespaces (add-watch/remove-watch) — refs are out of scope pending the
+  concurrency design note.
+- **parse-uuid strictness** (spec §9, parse-uuid S3): jolt is deliberately
+  strict where the reference's java.util.UUID accepts non-canonical forms
+  like `"0-0-0-0-0"`.
+- **vec of an array copies**: the reference ADOPTS an Object array (mutating
+  the array mutates the vector); jolt copies — immutable semantics win over
+  the implementation leak (`vec` namespace, one row).
+
+
+A future change that makes any of these rows pass will fail the cts gate as
+STALE, forcing this section and the baseline to be updated together.

test/conformance/known-divergences.edn

@@ -2,7 +2,7 @@
  "Rows of test/chez/corpus.edn whose :expected differs from reference JVM Clojure. The corpus is JVM-sourced (regen-corpus.clj), so this list is only the rows whose JVM value is an opaque host object that cannot round-trip to readable source — Java arrays, transients, atoms, beans, proxies, and chunks print as #object[..@addr] with a per-run identity — plus the (fn* foo) strictness case. For that the corpus keeps jolt's value. certify.clj gates on NEW (unlisted) divergences and STALE entries. Keyed by [suite label].",
  :legend
  {:numeric-model
-  "jolt has a numeric tower (exact integer / Ratio / double); no BigDecimal",
+  "jolt has the full numeric tower (exact integer / Ratio / double / BigDecimal); binary ops dispatch by operand category with JVM contagion rules",
   :host-model
   "no JVM host: classes->name strings, type->symbol, *in* is a map, inline-impl extenders, duck-typed with-open close",
   :reader-model

test/conformance/regen-corpus.clj

@@ -99,11 +99,12 @@
       [row :kept])))
 
 ;; --- corpus writer (preserves the one-row-per-line layout) -------------------
-(defn row-str [{:keys [suite label expected actual]}]
+(defn row-str [{:keys [suite label expected actual portability]}]
   (str "  {:suite " (pr-str suite)
        " :label " (pr-str label)
        " :expected " (if (= expected :throws) ":throws" (pr-str expected))
-       " :actual " (pr-str actual) "}"))
+       " :actual " (pr-str actual)
+       (when portability (str " :portability " portability)) "}"))
 
 (defn -main [& _]
   (let [corpus (edn/read-string (slurp corpus-path))