jolt/host/chez/lazy-bridge.ss
Yogthos bbca8bc0de Migrate list?/ratio?/rational? to the overlay; narrow jolt.host exposure
list?, ratio?, and rational? are the predicate-web members that are
genuinely safe to migrate: not extended at runtime, not on the compiler
emit/inference path, not reached by the kernel tier. They now live in the
overlay (clojure/core/20-coll.clj) built on the jolt.host tower/rep tests,
lowering to the same code the native shims did. Removed their native
definitions (predicates.ss) and, for ratio?/rational?, the now-redundant
post-prelude re-assertions. Also dropped the dead all-flonum overlay
ratio?/rational?/decimal? stubs.

The rest of the web stays native and is documented as such: map?/set?/
seq?/coll? are extended with sorted/record/lazy arms, decimal? is extended
by the optional bigdec module, integer?/float? are on the emit/inference
path, vector? is reached by the kernel-tier peek. jolt.host exposure is
therefore narrowed to just the tests these three consume (exact?,
rational-type?, cseq?, cseq-list?, empty-list?).

Numeric probe is byte-identical to pre-migration; list? correct across
list/vector/lazy/empty/cons/rest cases. Selfhost fixpoint holds, values/
unit/smoke/corpus green, bench flat within noise.
2026-06-30 11:10:36 -04:00

95 lines
4.9 KiB
Scheme

;; lazy-seq bridge — make-lazy-seq / coll->cells.
;;
;; The `lazy-seq` macro (00-syntax.clj) expands to
;; (make-lazy-seq (fn* [] (coll->cells (do body))))
;; and `lazy-cat` to (concat (lazy-seq c) ...). These back every overlay fn
;; built on lazy-seq — repeat / iterate / cycle / dedupe / take-nth / keep /
;; interpose / reductions / tree-seq (-> flatten) / lazy-cat.
;;
;; Bridge to the cseq model (seq.ss): a `jolt-lazyseq` is a deferred seq — a 0-arg
;; thunk that, when forced once, yields a seq (cseq | nil). coll->cells coerces the
;; body result to a seq (= jolt-seq), so the thunk already returns a seq; jolt-seq
;; is extended to force a lazyseq. The one trap: (cons x (a-lazy-seq)) must NOT
;; force the tail (else (repeat x) = (lazy-seq (cons x (repeat x))) loops forever),
;; so jolt-cons defers a lazyseq tail into a lazy cseq cell.
;;
;; Loaded LAST (after host-table.ss): %ls-seq then captures the fully-extended
;; jolt-seq (sorted-aware), so a lazy body returning a sorted coll still seqs.
(define-record-type jolt-lazyseq
(fields (mutable thunk) (mutable val) (mutable realized?))
(nongenerative jolt-lazyseq-v1))
(define (jolt-make-lazy-seq thunk) (make-jolt-lazyseq thunk jolt-nil #f))
;; force once and memoize. The thunk is (fn [] (coll->cells body)); coll->cells
;; already coerced the body to a seq (cseq | nil) via the live jolt-seq, so the
;; result needs no further coercion (a nested lazyseq was forced by coll->cells).
(define (force-lazyseq x)
(if (jolt-lazyseq-realized? x)
(jolt-lazyseq-val x)
(let ((r (jolt-invoke (jolt-lazyseq-thunk x))))
(jolt-lazyseq-val-set! x r)
(jolt-lazyseq-realized?-set! x #t)
(jolt-lazyseq-thunk-set! x #f)
r)))
;; coll->cells: coerce the body result to the cell representation = a seq | nil.
(define (jolt-coll->cells c) (jolt-seq c))
;; extend jolt-seq to force a lazyseq (a lazyseq is seqable -> its realized seq).
(define %ls-seq jolt-seq)
(set! jolt-seq (lambda (x) (if (jolt-lazyseq? x) (force-lazyseq x) (%ls-seq x))))
;; (cons x lazyseq): keep the tail lazy — force it only when the cseq cell is
;; walked, so an infinite (repeat/iterate/cycle) stays productive.
(define %ls-cons jolt-cons)
(set! jolt-cons (lambda (x coll)
(if (jolt-lazyseq? coll)
(cseq-lazy x (lambda () (force-lazyseq coll)))
(%ls-cons x coll))))
;; (conj lazyseq x): conj onto a seq prepends, like any seq — (conj (rest xs) y).
;; rest returns a lazyseq, so this is a common path; without it conj reports the
;; lazyseq as an "unsupported collection".
(define %ls-conj1 jolt-conj1)
(set! jolt-conj1 (lambda (coll x)
(if (jolt-lazyseq? coll) (jolt-cons x coll) (%ls-conj1 coll x))))
;; A lazyseq is a NEW value type, so the dispatchers that DON'T route through
;; jolt-seq must learn it or a raw (unrealized) lazyseq escapes — e.g. the corpus
;; compares (= [1 3 5] (take-nth 2 …)) against the raw lazyseq, and jolt=2 would
;; see an unknown type and return false. Recognizing it as sequential is enough
;; for equality + hash (seq=? / seq-hash coerce via jolt-seq); count / empty? /
;; nth / the printers don't, so coerce those explicitly.
(define %ls-sequential? jolt-sequential?)
(set! jolt-sequential? (lambda (x) (or (jolt-lazyseq? x) (%ls-sequential? x))))
(define %ls-count jolt-count)
(set! jolt-count (lambda (x) (if (jolt-lazyseq? x) (%ls-count (jolt-seq x)) (%ls-count x))))
(define %ls-empty? jolt-empty?)
(set! jolt-empty? (lambda (x) (if (jolt-lazyseq? x) (%ls-empty? (jolt-seq x)) (%ls-empty? x))))
(define %ls-nth jolt-nth)
(set! jolt-nth (case-lambda
((coll i) (if (jolt-lazyseq? coll) (%ls-nth (jolt-seq coll) i) (%ls-nth coll i)))
((coll i d) (if (jolt-lazyseq? coll) (%ls-nth (jolt-seq coll) i d) (%ls-nth coll i d)))))
;; a lazy seq prints as its realized seq — force, then re-dispatch through the
;; printer. An empty realized lazy seq is still a sequence, printing "()" (like a
;; JVM LazySeq), not "nil" — so (lazy-seq nil) and (rest '(1)) render "()".
(register-pr-str-arm! jolt-lazyseq?
(lambda (x) (let ((s (jolt-seq x))) (if (jolt-nil? s) "()" (jolt-pr-str s)))))
(register-pr-readable-arm! jolt-lazyseq?
(lambda (x) (let ((s (jolt-seq x))) (if (jolt-nil? s) "()" (jolt-pr-readable s)))))
(register-str-render! jolt-lazyseq?
(lambda (x) (let ((s (jolt-seq x))) (if (jolt-nil? s) "()" (jolt-str-render-one s)))))
;; seq? — a lazy seq IS a seq (predicates.ss's jolt-seq? predates the lazyseq
;; record). Unlike the native-op dispatchers above (called via a direct top-level
;; reference, so the set! is enough), seq? is reached through var-deref, which
;; reads the var-cell root — so the patched closure must be re-def-var!'d, not just
;; set!. (Exposed once dynamic binding let with-in-str/line-seq reach seq?.)
(define %ls-seq? jolt-seq?)
(set! jolt-seq? (lambda (x) (or (jolt-lazyseq? x) (%ls-seq? x))))
(def-var! "clojure.core" "seq?" jolt-seq?)
(def-var! "clojure.core" "make-lazy-seq" jolt-make-lazy-seq)
(def-var! "clojure.core" "coll->cells" jolt-coll->cells)