Chez Phase 1 (increment 2): live analyzer -> Chez, var cells, RT, mandelbrot

Wire the real pipeline end to end: host/chez/driver.janet boots a compile-mode
jolt ctx, runs the EXISTING Janet-hosted analyzer on actual Clojure source to
real IR, feeds it to the Scheme emitter, and runs the result on Chez. Analysis
stays on Janet (the analyzer ports to Chez in Phase 2); execution is on Chez.

emit.janet now consumes live IR (pv/phm-normalized like the Janet backend) and
covers what the analyzer actually emits, not the hand-built inc-1 shapes:
- core ops arrive as :var clojure.core/+ etc., not :rt — lowered to native
  Scheme via a native-ops table (mirrors backend.janet's), `=` to jolt=.
- var cells (host/chez/rt.ss): :def -> def-var!, :var -> var-deref. Late binding
  so cross-var calls (run -> count-point) and the entry crossing resolve at use.
- named fns (defn / fn self-name) bind via letrec so self-recursion resolves.
- unsupported stdlib/host refs (no core on Chez yet) are rejected at EMIT time
  (clean out-of-subset signal) instead of deref'ing to nil and failing at runtime.

Number model: jolt is all-doubles (no ratios; (/ 1 2) is 0.5), so literals emit
as flonums — matches the Janet host and keeps Chez out of exploding exact
rationals (mandelbrot). jolt-num->string prints integer-valued without ".0".

Two real bugs found via the corpus probe and fixed (regression rows added):
- loop bound in parallel (Scheme named-let) but Clojure loop is sequential — a
  later init must see earlier bindings; wrap a let* around the loop.
- #(...) shorthand gensyms params with a trailing `#`, invalid in Scheme — munge
  it to `_`.

Gate: test/chez/emit-test.janet runs the real analyzer -> Chez for (+ 1 2),
fib(30)=832040, mandelbrot run(40), and the two regressions, parity-checked
against the Janet oracle (6/6). First parity number via the new subset probe
(test/chez/run-corpus-chez.janet, JOLT_CHEZ_CORPUS=1): 182/182 compiled corpus
cases pass, 0 divergences; 2473/2655 out of subset pending core on Chez. Full
jpm/run-tests gate green (125 files). Chez tests skip cleanly without `chez`.

Perf note (unchanged plan): emitted fib(30) ~23ms vs hand-Scheme ~5ms — the
jolt-truthy? wrapper (~3x) plus flonum (not fixnum) arithmetic, both Phase-4
type-specialization levers.

test/chez/README.md

@@ -36,3 +36,21 @@ gate's job is to catch *regressions* the port introduces, not to bless these.
 The runner tests through `jolt -e`, exactly how the Chez host will be exercised —
 not the in-process `eval-string` the Janet `defspec` harness uses. The two differ
 on a handful of cases (the allowlist), and the CLI boundary is the portable one.
+
+## Phase 1 — first parity number (subset probe)
+The full `run-corpus.janet` gate drives an `-e`-capable jolt binary; the Chez
+host can't answer arbitrary `-e` until all of clojure.core is bootstrapped onto
+Chez (Phase 2). Until then, `run-corpus-chez.janet` reports parity for the subset
+the Phase-1 back end (`host/chez/emit.janet`) can already compile: each case is
+run through the live analyzer → Scheme emitter → Chez via `host/chez/driver`.
+Cases that reference unimplemented stdlib/host fns fail to EMIT (a clean
+compile-time signal) and are counted "out of subset", not as divergences.
+
+    JOLT_CHEZ_CORPUS=1 janet test/chez/run-corpus-chez.janet
+
+Baseline (2026-06-17): **182/182 compiled cases pass, 0 divergences**; 2473/2655
+out of subset (await core on Chez). It's a slow report (a Chez subprocess per
+case), so it's gated behind `JOLT_CHEZ_CORPUS` out of the default suite, like the
+benches. `test/chez/emit-test.janet` is the fast Phase-1 unit gate (real
+analyzer → Chez parity for fib/mandelbrot + regressions); both skip cleanly when
+`chez` isn't on PATH.

test/chez/emit-test.janet

@@ -1,73 +1,100 @@
-# Phase 1 — IR -> Scheme emitter tests. Hand-built IR in the real ir.clj shapes,
-# emitted to Scheme, compiled+run on Chez, results + fib speed checked.
+# Phase 1 (jolt-cf1q.2) — REAL pipeline end to end: actual Clojure source ->
+# Janet-hosted analyzer -> host-neutral IR -> Scheme emitter -> run on Chez.
+# Correctness is checked by parity against the SAME program evaluated by the
+# Janet host (jolt's own oracle), so a divergence is the back end's, not the
+# program's.
 #   janet test/chez/emit-test.janet      (from repo root)
-(import ../../host/chez/emit :as e)
+(import ../../src/jolt/api :as api)
+(import ../../src/jolt/backend :as backend)
+(import ../../src/jolt/reader :as r)
+(import ../../host/chez/driver :as d)
+(import ../../host/chez/emit :as emit)
 
-(defn run-chez [src]
-  (spit "/tmp/emit-prog.ss" src)
-  (def proc (os/spawn ["chez" "--script" "/tmp/emit-prog.ss"] :p {:out :pipe :err :pipe}))
-  (def out (ev/read (proc :out) 0x100000))
-  (def err (ev/read (proc :err) 0x100000))
-  (def code (os/proc-wait proc))
-  [code (string/trim (if out (string out) "")) (string/trim (if err (string err) ""))])
+(unless (d/chez-available?)
+  (print "skip: chez not on PATH")
+  (os/exit 0))
 
 (var total 0) (var fails 0)
-(defn ok [name pred] (++ total) (unless pred (++ fails) (printf "FAIL: %s" name)))
+(defn ok [name pred &opt extra]
+  (++ total)
+  (if pred (printf "ok: %s" name)
+    (do (++ fails) (printf "FAIL: %s   %s" name (or extra "")))))
 
-# --- IR builders (ir.clj shapes) ---
-(defn rt [name & args] {:op :invoke :fn {:op :rt :name name} :args args})
-(defn lcl [n] {:op :local :name n})
-(defn k [v] {:op :const :val v})
+# Janet-host oracle: evaluate the same program, stringify its value the way jolt
+# prints it at the CLI (so "832040" not "832040.0", "0.5" not 1/2, etc.).
+(def oracle-ctx (api/init {:compile? true}))
+(defn oracle [src] (string (api/load-string oracle-ctx src)))
 
-# 1) (+ 1 2)
-(def add-ir (rt "+" (k 1) (k 2)))
-(let [[code out err] (run-chez (e/program [] (e/emit add-ir)))]
-  (ok "(+ 1 2) = 3" (and (= code 0) (= out "3")))
-  (when (not= code 0) (printf "  err: %s" err)))
+(def ctx (d/make-ctx))
 
-# 2) fib def + (fib 30)
-(defn fib-call [arg] {:op :invoke :fn {:op :var :ns "user" :name "fib"} :args [arg]})
-(def fib-def
-  {:op :def :ns "user" :name "fib"
-   :init {:op :fn :name "fib"
-          :arities [{:params ["n"]
-                     :body {:op :if
-                            :test (rt "<" (lcl "n") (k 2))
-                            :then (lcl "n")
-                            :else (rt "+" (fib-call (rt "-" (lcl "n") (k 1)))
-                                          (fib-call (rt "-" (lcl "n") (k 2))))}}]}})
-(let [prog (e/program [(e/emit fib-def)] (e/emit (fib-call (k 30))))
-      [code out err] (run-chez prog)]
-  (ok "(fib 30) = 832040" (and (= code 0) (= out "832040")))
-  (when (not= code 0) (printf "  err: %s" err)))
+# 1) constant-folded arithmetic: (+ 1 2) -> the analyzer folds to const 3.
+(let [[code out err] (d/run-on-chez ctx "(+ 1 2)")]
+  (ok "(+ 1 2) = 3" (and (= code 0) (= out "3") (= out (oracle "(+ 1 2)"))) (string out " | " err)))
 
-# 3) loop/recur sum 1..5 = 15
-(def loop-ir
-  {:op :loop
-   :bindings [["i" (k 1)] ["acc" (k 0)]]
-   :body {:op :if
-          :test (rt ">" (lcl "i") (k 5))
-          :then (lcl "acc")
-          :else {:op :recur :args [(rt "inc" (lcl "i")) (rt "+" (lcl "acc") (lcl "i"))]}}})
-(let [[code out err] (run-chez (e/program [] (e/emit loop-ir)))]
-  (ok "loop/recur sum = 15" (and (= code 0) (= out "15")))
-  (when (not= code 0) (printf "  err: %s" err)))
+# 2) fib: var-cell def + named-fn self-recursion + native arith, via real IR.
+(let [src "(defn fib [n] (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2))))) (fib 30)"
+      [code out err] (d/run-on-chez ctx src)]
+  (ok "(fib 30) = 832040" (and (= code 0) (= out "832040") (= out (oracle src))) (string out " | " err)))
 
-# 4) speed: emitted fib(30) should hit ~the spike ceiling (hand-Scheme ~5ms),
-#    proving the IR->Scheme path adds no overhead vs hand-written Scheme.
-(def timed-fib
-  (string (e/emit fib-def) "\n"
-          "(define (now-ns) (let ((t (current-time 'time-monotonic))) (+ (* (time-second t) 1000000000) (time-nanosecond t))))\n"
-          "(fib 24)(fib 24)\n"
-          "(let* ((t0 (now-ns)) (r (fib 30)) (ms (/ (- (now-ns) t0) 1000000.0)))\n"
-          "  (printf \"~a ~a\\n\" r (exact->inexact ms)))"))
-(let [[code out err] (run-chez (string "(import (chezscheme))\n(load \"host/chez/values.ss\")\n(define (jolt-inc x) (+ x 1))\n" timed-fib))]
+# 3) mandelbrot kernel: loop/recur, let, or-expansion, cross-var call
+#    (run -> count-point), flonum compute. Parity vs the Janet host on run(40).
+(def mandel-defs ``
+(defn count-point [cr ci cap]
+  (loop [i 0 zr 0.0 zi 0.0]
+    (if (or (>= i cap) (> (+ (* zr zr) (* zi zi)) 4.0))
+      i
+      (recur (inc i)
+             (+ (- (* zr zr) (* zi zi)) cr)
+             (+ (* 2.0 (* zr zi)) ci)))))
+(defn run [n]
+  (let [cap 200
+        nd (* 1.0 n)]
+    (loop [y 0 acc 0]
+      (if (< y n)
+        (let [ci (- (/ (* 2.0 y) nd) 1.0)
+              row (loop [x 0 a 0]
+                    (if (< x n)
+                      (let [cr (- (/ (* 2.0 x) nd) 1.5)]
+                        (recur (inc x) (+ a (count-point cr ci cap))))
+                      a))]
+          (recur (inc y) (+ acc row)))
+        acc))))
+``)
+(let [src (string mandel-defs "\n(run 40)")
+      [code out err] (d/run-on-chez ctx src)]
+  (ok "mandelbrot run(40) parity" (and (= code 0) (= out (oracle src)))
+      (string "chez=" out " janet=" (oracle src) " | " err)))
+
+# 3b) regressions found via the corpus probe:
+#   - loop binds SEQUENTIALLY (Scheme named-let is parallel); b must see a.
+#   - #(...) shorthand gensyms params with a trailing `#` (invalid in Scheme).
+(each [label src] [["loop sequential init" "(loop [a 1 b (+ a 10)] (+ a b))"]
+                   ["#() shorthand" "(#(+ %1 %2) 1 2)"]]
+  (let [[code out err] (d/run-on-chez ctx src)]
+    (ok label (and (= code 0) (= out (oracle src))) (string "chez=" out " janet=" (oracle src) " | " err))))
+
+# 4) perf signal: emitted fib(30) in-Scheme timing (excludes Chez startup), to
+#    track against the spike ceiling (hand-Scheme fib ~5ms). Informational — the
+#    jolt-truthy? wrapper (~3x) and flonum modeling are known Phase-4 levers.
+(let [fib-ir (backend/analyze-form ctx (in (r/parse-next "(defn fib [n] (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2)))))") 0))
+      fib-scm (emit/emit fib-ir)
+      timed (string "(import (chezscheme))\n(load \"host/chez/rt.ss\")\n"
+                    fib-scm "\n"
+                    "(define fib (var-deref \"user\" \"fib\"))\n"
+                    "(define (now-ns) (let ((t (current-time 'time-monotonic))) (+ (* (time-second t) 1000000000) (time-nanosecond t))))\n"
+                    "(fib 24)(fib 24)\n"
+                    "(let* ((t0 (now-ns)) (r (fib 30)) (ms (/ (- (now-ns) t0) 1000000.0)))\n"
+                    "  (printf \"~a ~a\\n\" (jolt-pr-str r) (exact->inexact ms)))")]
+  (spit "/tmp/chez-jolt-fib-timed.ss" timed)
+  (def proc (os/spawn ["chez" "--script" "/tmp/chez-jolt-fib-timed.ss"] :p {:out :pipe :err :pipe}))
+  (def out (string/trim (string (ev/read (proc :out) 0x100000))))
+  (def err (string/trim (string (or (ev/read (proc :err) 0x100000) ""))))
+  (def code (os/proc-wait proc))
   (def parts (string/split " " out))
   (def result (get parts 0))
   (def ms (scan-number (or (get parts 1) "999")))
-  (ok "emitted fib(30) correct + fast" (and (= code 0) (= result "832040") (< ms 40)))
-  (printf "  emitted fib(30): %s in %.2f ms (hand-Scheme spike ~5ms)" result ms)
-  (when (not= code 0) (printf "  err: %s" err)))
+  (ok "timed fib(30) correct" (and (= code 0) (= result "832040")) (string out " | " err))
+  (printf "  emitted fib(30): %s in %.2f ms (hand-Scheme spike ~5ms)" result ms))
 
 (printf "\nemit-test: %d/%d passed" (- total fails) total)
 (os/exit (if (> fails 0) 1 0))

test/chez/run-corpus-chez.janet

@@ -0,0 +1,58 @@
+# Phase 1 (jolt-cf1q.2) — FIRST parity number for the Chez back end.
+#
+# The full 0b gate (test/chez/run-corpus.janet) drives an `-e`-capable jolt
+# binary; that needs all of clojure.core bootstrapped onto Chez, which is Phase 2.
+# Until then, this probe reports parity for the subset the back end can ALREADY
+# compile: each corpus case `(= expected actual)` is run through the live
+# analyzer -> Scheme emitter -> Chez. Cases that reference unimplemented core fns
+# fail to EMIT (a clean compile-time signal) and are counted "out of subset",
+# not as divergences. The number to watch is parity WITHIN the compiled subset.
+#   janet test/chez/run-corpus-chez.janet
+#   JOLT_CORPUS_LIMIT=400 …    (every-Nth stride, fast)
+(import ../../host/chez/driver :as d)
+
+# Slow reporting tool (~20s: a Chez subprocess per compiled case), not a pass/fail
+# unit test — gate it out of the default suite like the benches (JOLT_BENCH).
+(unless (os/getenv "JOLT_CHEZ_CORPUS")
+  (print "skip: set JOLT_CHEZ_CORPUS=1 to run the Chez subset parity probe")
+  (os/exit 0))
+(unless (d/chez-available?)
+  (print "skip: chez not on PATH")
+  (os/exit 0))
+
+(def corpus (parse (slurp "test/chez/corpus.edn")))
+(def cases
+  (if-let [n (os/getenv "JOLT_CORPUS_LIMIT")]
+    (let [stride (max 1 (math/floor (/ (length corpus) (scan-number n))))]
+      (seq [i :range [0 (length corpus) stride]] (in corpus i)))
+    corpus))
+
+(def ctx (d/make-ctx))
+(var compiled 0) (var pass 0) (var out-of-subset 0)
+(def diverged @[])
+
+(each row cases
+  (def {:expected e :actual a :label l} row)
+  # :throws cases need error-semantics we don't model yet — skip.
+  (if (= e :throws)
+    (++ out-of-subset)
+    (let [src (string "(= " e " " a ")")
+          # compile-program can throw (unsupported op/core fn) or the analyzer can
+          # punt; either way the case is outside the compilable subset.
+          res (try (d/run-on-chez ctx src) ([err] :uncompilable))]
+      (if (= res :uncompilable)
+        (++ out-of-subset)
+        (let [[code out] res]
+          (++ compiled)
+          (cond
+            (not= code 0) (array/push diverged [l (string "exit " code)])
+            (= out "true") (++ pass)
+            (array/push diverged [l (string "got " out)])))))))
+
+(printf "\nChez subset parity: %d/%d compiled cases pass  (%d/%d corpus out of subset)"
+        pass compiled out-of-subset (length cases))
+(when (> (length diverged) 0)
+  (printf "%d divergence(s) within the compiled subset:" (length diverged))
+  (each [l m] (slice diverged 0 (min 25 (length diverged)))
+    (printf "  [%s] %s" l m)))
+(flush)