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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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7
host/chez/emit.janet
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@ -331,6 +331,13 @@
# keyword/coll/fn) -> dynamic IFn dispatch. Excludes the named-fn self-call.
(and (= :local (get fnode :op)) (not (get known-procs (munge (get fnode :name)))))
(string "(jolt-invoke " (emit fnode) " " (string/join args " ") ")")
# a late-bound :var call head can hold a plain procedure OR a non-applicable
# value the RT dispatches (a multimethod record, a keyword/coll IFn) — route it
# through jolt-invoke so all of those work. Transparent for a procedure
# (jolt-invoke just applies it); the hot self-recursive call is a :local
# known-proc above, so it stays a direct call.
(= :var (get fnode :op))
(string "(jolt-invoke " (emit fnode) " " (string/join args " ") ")")
(string "(" (emit fnode) " " (string/join args " ") ")")))
(set emit (fn emit [node]