jolt/test/chez/README.md
Yogthos ffa122440a Chez Phase 1 (increment 3e): throw/try/catch/finally + ex-info
Emit :throw as jolt-throw (Scheme raise of the raw jolt value, matching the
Janet compiled back end's (error v) — no envelope, so catch binds it directly).
Emit :try as guard (catch; the class is dropped in the IR, so it's catch-all)
plus dynamic-wind for finally. ex-info is a native-op building the tagged jolt
map {:jolt/type :jolt/ex-info :message :data :cause}, so the ex-data/ex-message/
ex-cause tier fns read it over jolt-get for free.

Prelude emit reach 303 -> 334/355 (:throw and :try gaps close). Subset probe
619 -> 632/632 compiled, 0 divergences (throw/try/ex-info pull 13 corpus cases
into the subset). emit-test 94/94 (added 11 throw/try/ex-info cases + uncaught
exits non-zero). Full gate green.
2026-06-17 17:10:38 -04:00

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Markdown

# Chez port — Phase 0 test contract harness
The host-neutral correctness gate for the Chez re-host (epic jolt-cf1q). The
spec corpus is data, so the SAME contract validates every host.
## Files
- `extract-corpus.janet` — parses `test/spec/*.janet` `(defspec …)` tables as
data and writes `corpus.edn` (2655 `[label expected actual]` cases). The file
is valid as BOTH EDN (a future Chez-jolt runner) and Janet data (the runner
below). Regenerate: `janet test/chez/extract-corpus.janet`.
- `corpus.edn` — the extracted contract (generated; checked in for convenience).
- `run-corpus.janet` — drives a TARGET jolt binary, one fresh subprocess per case
(fresh ctx = per-case isolation), checking `(= expected actual)` prints `true`
at the CLI, or that a `:throws` case exits non-zero. Pluggable target:
- `janet test/chez/run-corpus.janet` # default build/jolt
- `JOLT_BIN=build/jolt-chez janet test/chez/run-corpus.janet` # Phase 1+
- `JOLT_CORPUS_LIMIT=400 …` # every-Nth stride, fast
- `known-divergences.edn` — allowlist of cases that diverge at the CLI boundary.
The gate fails only on a NEW divergence; known ones are reported but tolerated.
- `values-test.ss` / `../../host/chez/values.ss` — Phase 0a value model + tests.
## The reference baseline (2026-06-17, Janet `build/jolt`, compile mode)
2641/2655 pass; 14 known divergences. They split into:
- **interpret-vs-compile leniency** — `:throws` cases where interpret mode raises
but compile mode returns (`< nil`, `> with nil`, `neg? keyword`, `max`/`min-key`
on non-numbers). Several are also non-canonical vs JVM Clojure.
- **invoke-collection-as-fn** — the `transient / invokable lookup` suite invokes
transients/collections as fns (`((transient {:x 7}) :x)`); compile mode (and
JVM Clojure) reject it.
- **`xml-seq walks`** — one structural case.
The compile-only Chez host (JVM-canonical oracle) should MATCH OR FIX these. The
gate's job is to catch *regressions* the port introduces, not to bless these.
## Why the CLI boundary
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 after inc 3e (throw/try + ex-info): **632/632 compiled cases pass**, 0
divergences; 2023/2655 out of subset (await clojure.core on Chez). Inc 3c
(multi-arity + variadic fns) brought this to 619/619 — `emit-fn` lowers
multi-arity fns to a Scheme `case-lambda` and variadic fns to a rest-arg lambda
(the Scheme rest list is coerced to a jolt seq, nil when empty); inc 3e's
throw/try/ex-info support pulled 13 more corpus cases into the subset.
## Phase 1 — clojure.core prelude emission (inc 3d, jolt-ocvi)
The `-e`-capable jolt-chez path: emit the clojure.core tiers
(`jolt-core/clojure/core/NN-*.clj`) through the same analyzer → emit pipeline as a
Scheme PRELUDE of `def-var!` forms, so user code's `(var-deref "clojure.core" …)`
resolves the fn at runtime. `emit/set-prelude-mode!` flips a switch: in the default
(subset) mode a non-native `clojure.core` ref is rejected ("out of subset"); in
prelude mode it lowers to a runtime `var-deref` so core fns chain through each
other. Host interop (`:host`) and unhandled IR ops still error in both modes —
those are the real gaps that need a hand-written RT shim or new emit support.
`core-prelude-probe.janet` (gated behind `JOLT_CHEZ_PRELUDE=1`) measures reach and
catalogs the gaps; macros are skipped (analyze-time only, not a runtime value):
JOLT_CHEZ_PRELUDE=1 janet test/chez/core-prelude-probe.janet
Baseline after inc 3e (throw/try + ex-info): **334/355 non-macro core forms emit**
to Scheme (was 303 at inc 3d). `:throw` lowers to `jolt-throw` (Scheme `raise` of
the raw jolt value, like the Janet compiled back end); `:try` lowers to `guard`
(catch, class dropped → catch-all) + `dynamic-wind` (finally); `ex-info` is a
native-op building the tagged jolt map, so the ex-data/ex-message/ex-cause tier
fns read it over `get` for free. Remaining 21 gaps: `:quote` (8, needs RT
symbols/lists), Java host interop `.write`/`.isDirectory` (6, io tier), `letfn`
(4), `declare`/def-no-init (2), one edge (`parse-uuid`). Each is a clean
next-increment target. The probe has a regression floor (raise it as gaps close).
Prior, inc 3b (seq tier + dynamic IFn, jolt-5pso): 595/595 compiled, 0 divergences,
2060/2655 out of subset. The seq tier brought up a list/lazy-seq type with
first/rest/next/seq/cons/list, map/filter/reduce/into/remove,
range/take/drop/concat/apply, keys/vals, and nth/peek/pop over seqs; dynamic IFn
dispatch (a keyword/vector/coll held in a local and called as a fn) routes through
the `jolt-invoke` fallback, closing the 3 ex-known divergences. The probe exits
non-zero on any NEW divergence.
(Prior, inc 3a: 433/436 compiled, 3 known IFn divergences, 2219 out of subset.
Inc 2: 182/182 compiled, 0 divergences, 2473 out of subset.)
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 + collections + regressions); both skip cleanly when
`chez` isn't on PATH.