jolt/host/chez/vars.ss
Yogthos acf3e1ffd3 refactor: registry pattern for jolt-get + jolt=2 (jolt-lmot)
jolt-get (4 sites: host-table/natives-misc/inst-time/records) and jolt=2 (6 sites:
records/vars/inst-time/natives-misc/bigdec/host-table) move off the set!-rebind
chains to register-get-arm! / register-eq-arm!. get's case-lambda becomes a stable
2/3-arg entry over a 3-arg dispatch; the equality arm pred is (a b) since either arg
may carry the type, and the host-table sorted arm normalizes-then-re-dispatches.

Behaviour-preserving (runtime .ss): var/inst/bigdec/record/uuid equality, record!=map,
sorted-map=plain-map, and all the get cases verified; make test green, 0 new corpus
divergences. Four of six dispatchers done; the printer (pr-str/pr-readable) remains.
2026-06-23 23:12:08 -04:00

53 lines
2.4 KiB
Scheme

;; vars as first-class objects — (var x) / #'x.
;;
;; The emitter lowers :the-var to (jolt-var ns name) — the rt.ss var-cell, which
;; is now also a Clojure VAR value. var? / var-get / deref-of-var / var-as-IFn /
;; var equality / pr-str(#'ns/name) operate on it. bound? is overridden natively
;; in post-prelude.ss (the overlay reads (get v :root), nil on a record).
;;
;; Dynamic binding (binding / with-bindings* / var-set / thread-bound? /
;; with-redefs) lives in dyn-binding.ss, which chains the var-read paths set up
;; here.
;;
;; Loaded LAST (after natives-xform.ss): chains jolt-deref (atom/volatile arms)
;; and the printers.
(define (jolt-var-pred? x) (var-cell? x))
;; the var's current root; unbound is an error (Clojure throws on an unbound var).
(define (jolt-var-get v)
(if (var-cell? v)
(let ((r (var-cell-root v)))
(if (eq? r jolt-unbound) (error #f "Unbound var" v) r))
(error #f "var-get: not a var" v)))
;; deref of a var -> its root.
(define %v-deref jolt-deref)
(set! jolt-deref (lambda (x) (if (var-cell? x) (jolt-var-get x) (%v-deref x))))
;; a var is an IFn — invoking it invokes its root value ((var f) args -> (f args)).
(define %v-invoke jolt-invoke)
(set! jolt-invoke (lambda (f . args)
(if (var-cell? f) (apply jolt-invoke (var-cell-root f) args) (apply %v-invoke f args))))
;; two var cells are = iff same ns/name (Clojure var identity).
(register-eq-arm! (lambda (a b) (or (var-cell? a) (var-cell? b)))
(lambda (a b) (and (var-cell? a) (var-cell? b)
(string=? (var-cell-ns a) (var-cell-ns b))
(string=? (var-cell-name a) (var-cell-name b)))))
;; pr-str / str of a var -> #'ns/name.
(define (var->str v) (string-append "#'" (var-cell-ns v) "/" (var-cell-name v)))
(define %v-pr-str jolt-pr-str)
(set! jolt-pr-str (lambda (x) (if (var-cell? x) (var->str x) (%v-pr-str x))))
(define %v-pr-readable jolt-pr-readable)
(set! jolt-pr-readable (lambda (x) (if (var-cell? x) (var->str x) (%v-pr-readable x))))
(register-str-render! var-cell? var->str)
;; bound? — native (the overlay's (get v :root) is nil on a var-cell record).
(define (jolt-var-bound-one? v) (and (var-cell? v) (not (eq? (var-cell-root v) jolt-unbound))))
(define (jolt-bound? . vars) (if (for-all jolt-var-bound-one? vars) #t #f))
(def-var! "clojure.core" "var?" jolt-var-pred?)
(def-var! "clojure.core" "var-get" jolt-var-get)
(def-var! "clojure.core" "deref" jolt-deref)