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Chez Phase 1 (increment 3q): multimethod dispatch + late-bind

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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).
This commit is contained in:
Yogthos 2026-06-18 01:24:01 -04:00
parent e51cc2e47e
commit 02139af0a1
10 changed files with 279 additions and 8 deletions
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5
host/chez/rt.ss
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@ -165,3 +165,8 @@
;; reduced/reduced?/identical? — seed-native fns the overlay assumes are core
;; natives. Over the seq layer + jolt-compare, so loaded after converters.ss.
(load "host/chez/natives-seq.ss")
;; multimethods (jolt-9ls5): defmulti/defmethod dispatch runtime. Needs jolt-invoke
;; (seq.ss), jolt=/key-hash/jolt-hash-map (collections.ss), jolt-atom? (atoms.ss),
;; jolt-pr-str (above), and the var-cell machinery — so loaded last.
(load "host/chez/multimethods.ss")