jolt/host/chez/regex.ss
Yogthos e51cc2e47e Chez Phase 1 (increment 3p): misc seq/regex gaps + bug tracking
jolt-y1zq tail:
- 0-arg (conj) -> [] and 0-arg (conj!) -> a fresh transient vector
- nth sees through a transient (like get/count/contains?)
- irregex \p{...}/\P{...} property classes translate to the seed's ASCII char
  classes (regex.ss): \p{L} -> [a-zA-Z] + non-ASCII codepoints (the seed counts
  UTF-8 high bytes as letters), \p{N} -> [0-9], \p{Ps} -> [([{], etc. The
  translator tracks [...] nesting so a \p{} inside a class emits its content, not
  a nested class.

Two pre-existing bugs found and filed (tracked, not replicated):
- jolt-x0os: the Chez emitter mangles non-ASCII string literals into invalid Chez
  hex escapes (so p{L} utf-8 crashes on the input string, not the regex).
- jolt-ea9k: the seed's transient assoc! accepts odd args and assigns nil to the
  trailing key (non-Clojure; plain assoc throws). The Chez host throws
  (Clojure-correct); the 4 spec rows encoding the leniency are flagged in
  transients-spec.janet pending the seed fix.

Parity 1493 -> 1506/2497, 0 new divergences. emit-test 291/291.
2026-06-18 00:44:21 -04:00

138 lines
7 KiB
Scheme

;; Phase 1 (jolt-cf1q.2) — regex on Chez via vendored irregex (jolt-i0s3).
;;
;; jolt's seed regex (src/jolt/regex.janet) compiles patterns to Janet's PEG
;; engine; Chez has no regex at all. Rather than re-host that engine, we vendor
;; Alex Shinn's irregex (vendor/irregex, BSD) — a portable Scheme regex with
;; PCRE/Java-style STRING patterns — and wrap jolt's re-* surface over it.
;;
;; irregex maps cleanly onto the Clojure fns: irregex-match is an anchored
;; whole-string match (= re-matches), irregex-search finds the first match
;; anywhere (= re-find), irregex-match-substring extracts group N (0 = whole).
;; Results follow Clojure shape: a 0-group match is the whole string; a grouped
;; match is a jolt VECTOR [whole g1 ...] (a non-participating group is nil); a nil
;; result is jolt-nil; re-seq is a jolt seq (nil when there are no matches).
;;
;; The re-* fns are def-var!'d into clojure.core so prelude / -e code resolves
;; them at runtime (they're NOT subset native-ops: irregex's Unicode/property-
;; class semantics differ from the seed's byte-PEG approximation, so they stay out
;; of the subset-parity corpus). Loaded from rt.ss after def-var! is defined.
;; irregex.scm is portable R[457]RS; two small adaptations for Chez's top level:
;; a cond-expand at expression position (Chez's is library-only), and `error`
;; called with a lone string (Chez's error wants who+msg). The wrapper normalizes
;; both without changing behavior for valid patterns.
(define-syntax cond-expand
(syntax-rules (else)
((_ (else e ...)) (begin e ...))
((_ (else e ...) c ...) (begin e ...))
((_ (req e ...) c ...) (cond-expand c ...))
((_) (if #f #f))))
(define %chez-error error)
(define (error . args)
(if (and (pair? args) (string? (car args)))
(apply %chez-error #f args)
(apply %chez-error args)))
(load "vendor/irregex/irregex.scm")
;; Unicode property classes \p{...} (jolt-y1zq): irregex's string syntax has no
;; \p{...}, so translate the ones the seed's byte-PEG maps (src/jolt/regex.janet
;; prop-frag) to ASCII char classes before compiling. ASCII-only — the seed counts
;; UTF-8 high bytes as letters for \p{L}, which a Unicode-char Scheme string can't
;; reproduce byte-for-byte; the corpus tests ASCII inputs, where they agree. An
;; unmapped name is left as-is (irregex errors, as before — no new behavior). The
;; ORIGINAL source is kept for printing; only the compiled pattern is translated.
(define (prop-class name)
(cond
;; L/Alpha: ASCII letters + any non-ASCII codepoint (the seed counts UTF-8 high
;; bytes as letters, so ^\p{L}+$ accepts accented words). N/Z stay ASCII-only,
;; matching the seed's byte-PEG.
((or (string=? name "L") (string=? name "Alpha")) "a-zA-Z\\x80-\\x{10FFFF}")
((string=? name "Lu") "A-Z")
((string=? name "Ll") "a-z")
((or (string=? name "N") (string=? name "Nd") (string=? name "Digit")) "0-9")
((or (string=? name "Z") (string=? name "Zs")) " ")
((string=? name "Ps") "([{")
((string=? name "Pe") ")\\]}")
(else #f)))
;; Tracks whether the cursor is inside a [...] char class: a \p{X} there emits the
;; class CONTENT (the seed inlines it), standalone it emits a wrapping [X]. Escapes
;; (\[, \]) don't toggle the class. \P (negation) only wraps when standalone.
(define (translate-prop-classes src)
(let ((len (string-length src)) (out (open-output-string)))
(let loop ((i 0) (in-class #f))
(if (fx>=? i len)
(get-output-string out)
(let ((c (string-ref src i)))
(cond
;; \p{Name} / \P{Name}
((and (char=? c #\\) (fx<? (fx+ i 2) len)
(let ((p (string-ref src (fx+ i 1)))) (or (char=? p #\p) (char=? p #\P)))
(char=? (string-ref src (fx+ i 2)) #\{))
(let* ((close (let scan ((j (fx+ i 3)))
(cond ((fx>=? j len) #f)
((char=? (string-ref src j) #\}) j)
(else (scan (fx+ j 1))))))
(cls (and close (prop-class (substring src (fx+ i 3) close)))))
(cond
((not cls) (write-char c out) (loop (fx+ i 1) in-class))
(in-class (display cls out) (loop (fx+ close 1) in-class))
(else
(display "[" out)
(when (char=? (string-ref src (fx+ i 1)) #\P) (display "^" out))
(display cls out) (display "]" out)
(loop (fx+ close 1) in-class)))))
;; any other escape: copy the pair verbatim, don't toggle class state
((and (char=? c #\\) (fx<? (fx+ i 1) len))
(write-char c out) (write-char (string-ref src (fx+ i 1)) out)
(loop (fx+ i 2) in-class))
((and (not in-class) (char=? c #\[))
(write-char c out) (loop (fx+ i 1) #t))
((and in-class (char=? c #\]))
(write-char c out) (loop (fx+ i 1) #f))
(else (write-char c out) (loop (fx+ i 1) in-class))))))))
;; A jolt regex value: the source string (for printing / str) + the compiled
;; irregex. regex? recognizes it; the printer renders #"source".
(define-record-type regex-t (fields source irx) (nongenerative jolt-regex-v1))
(define (jolt-regex source) (make-regex-t source (irregex (translate-prop-classes source))))
(define (jolt-regex? x) (regex-t? x))
(define (jolt-re-pattern x) (if (regex-t? x) x (jolt-regex x)))
;; An irregex match -> the Clojure result: whole string (no groups) or the
;; [whole g1 ... gn] vector (nil for a non-participating group).
(define (irx-result m)
(let ((n (irregex-match-num-submatches m)))
(if (= n 0)
(irregex-match-substring m 0)
(let loop ((i n) (acc '()))
(if (< i 0)
(apply jolt-vector acc)
(let ((s (irregex-match-substring m i)))
(loop (- i 1) (cons (if s s jolt-nil) acc))))))))
(define (jolt-re-matches re s)
(let ((m (irregex-match (regex-t-irx (jolt-re-pattern re)) s)))
(if m (irx-result m) jolt-nil)))
(define (jolt-re-find re s)
(let ((m (irregex-search (regex-t-irx (jolt-re-pattern re)) s)))
(if m (irx-result m) jolt-nil)))
;; All non-overlapping matches, left to right. Advance past each match end (or by
;; one on a zero-width match). nil when there are no matches (Clojure: seq-able as
;; nil, so (if-let [m (re-seq ...)] ...) works), matching the seed.
(define (jolt-re-seq re s)
(let ((irx (regex-t-irx (jolt-re-pattern re)))
(len (string-length s)))
(let loop ((start 0) (acc '()))
(let ((m (and (<= start len) (irregex-search irx s start))))
(if m
(let ((e (irregex-match-end-index m 0)))
(loop (if (> e start) e (+ start 1)) (cons (irx-result m) acc)))
(list->cseq (reverse acc)))))))
(def-var! "clojure.core" "re-pattern" jolt-re-pattern)
(def-var! "clojure.core" "re-matches" jolt-re-matches)
(def-var! "clojure.core" "re-find" jolt-re-find)
(def-var! "clojure.core" "re-seq" jolt-re-seq)
(def-var! "clojure.core" "regex?" jolt-regex?)