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).
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