host/chez/multimethods.ss implements the multimethod runtime: defmulti/defmethod
expand to defmulti-setup/defmethod-setup calls (+ get-method/methods/
remove-method/prefer-method/prefers). A jolt-multifn record carries its dispatch
fn and a jolt=-keyed method table; jolt-invoke dispatches it (exact match, then
isa?/hierarchy with prefer-method, then :default), reusing the overlay's
isa?/derive/make-hierarchy. The multifn's ns comes from a runtime chez-current-ns
(default user; the prelude load sets clojure.core for print-method/print-dup).
Two emit-side changes were needed:
- late-bind (:late-bind-unresolved? ctx flag, default OFF): defmulti expands to a
bare-symbol setup call, so the analyzer doesn't intern the name and a forward
reference '(area ...)' after '(defmulti area ...)' in one form was 'Unable to
resolve symbol'. The strict compiler punts these to the interpreter; the Chez
back end has none, so the flag lowers an unresolved symbol to a var-ref against
the compile ns (open-world -e semantics). Set only by the Chez make-ctx /
jolt-chez; the main compiler keeps strict resolution (host_iface late-bind?
defaults nil).
- a :var call head now routes through jolt-invoke, since a late-bound var can hold
a multifn (or keyword/coll IFn), not just a procedure. Transparent for
procedures; the hot self-recursive call is a :local known-proc, stays direct.
Class-based dispatch ((class x)/String) deferred (needs deftype/class subsystem).
Parity 1506 -> 1530/2497, 0 new divergences. emit-test 302/302. Full janet gate
green (the analyzer flag is off there; suite flakiness under parallel load only).
Emit every non-macro clojure.core form through the live analyzer -> Chez emit
pipeline as a def-var! prelude (prelude mode, tier dependency order), load it
before a user expression, and you get an -e-capable jolt-chez: analysis on Janet,
execution on Chez. driver/emit-core-prelude assembles it (each form behind a
silent load guard so the Phase-2 multimethod forms don't break the rest);
bin/jolt-chez is the -e CLI, caching the prelude on disk keyed by source hash.
run-corpus-prelude.janet is the full parity gate this opens, the prelude-backed
sibling of run-corpus-chez. First baseline: 1220/2497 evaluated cases pass, 0 new
divergences (10 allowlisted: dynamic vars, class names, eval-order — deferred
Phase 2). The rest is the punch-list: ~360 emit-fail (real host interop, out of
the analyzer subset) and ~900 runtime crashes, mostly core fns calling
host-coupled seed natives with no Chez shim yet (str/format/vec, transients).
Follow-ups jolt-t6cr/kl2l/q3w8/9ls5.
Two shims landed to get the prelude to load and run. atoms.ss: atom/deref/swap!/
reset! (+ the compare/vals kernel) — needed at load time for
global-hierarchy = (atom (make-hierarchy)). predicates.ss: the type predicates +
name/namespace/boolean the overlay assumes are seed natives, matching the seed's
strict semantics. post-prelude.ss re-asserts char?/atom? after the prelude: the
overlay implements those by reading :jolt/type, which is false for Chez-native
chars/atoms, so its def-var! would clobber the correct native versions.
Per-case Scheme files are PID-unique so a foreground -e never reads a half-written
file while the gate runs.
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.
