ocaml: phase 5.1 baseline OCaml programs (5/5 pass) + lookahead boundary
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lib/ocaml/baseline/{factorial,list_ops,option_match,module_use,sum_squares}.ml
exercised through ocaml-run-program (file-read F). lib/ocaml/baseline/
run.sh runs them and compares against expected.json — all 5 pass.

To make module_use.ml (with nested let-in) parse, parser's
skip-let-rhs-boundary! now uses has-matching-in? lookahead: a let at
depth 0 in a let-decl rhs opens a nested block IFF a matching in
exists before any decl-keyword. Without that in, the let is a new
top-level decl (preserves test 274 'let x = 1 let y = 2').

This is the first piece of Phase 5.1 'vendor a slice of OCaml
testsuite' — handcrafted fixtures for now, real testsuite TBD.
This commit is contained in:
2026-05-08 13:33:24 +00:00
parent 756d5fba64
commit de7be332c8
9 changed files with 217 additions and 17 deletions

View File

@@ -895,12 +895,88 @@
(fn
()
(let ((t (peek-tok))) (if (= t nil) (len src) (get t :pos)))))
;; skip-to-boundary! advances `idx` to the next top-level decl
;; boundary, tracking `let`/`begin`/`struct` etc. nesting so that
;; an inner `let ... in ...` doesn't terminate a top-level decl
;; body. Boundary tokens (when at depth 0):
;; ;; let module open include and type exception
;; Boundary at any depth: eof.
;; Two flavors of boundary skipping:
;;
;; * `skip-to-decl-boundary!` — used by parse-decl-expr. Stops
;; at the start of the next top-level decl: ;;, let, module,
;; open, include, and, type, exception, or eof.
;;
;; * `skip-let-rhs-boundary!` — used inside parse-decl-let after
;; the `=`. Treats `let` as the opener of a nested let..in
;; block (NOT a decl boundary), so `let f x = let y = 0 in y`
;; parses correctly. Boundary tokens (depth 0): ;;, module,
;; open, include, and, type, exception, or eof.
;; Lookahead: starting just past a `let` at the cursor, scan
;; for a matching `in` before the next decl boundary. Returns
;; true iff such an `in` exists — meaning the let is nested,
;; not a new decl.
(define has-matching-in?
(fn ()
(let ((p (+ idx 1)) (d 1) (result false) (done false))
(begin
(define scan
(fn ()
(when (not done)
(cond
((>= p tok-len) (set! done true))
(else
(let ((t (nth tokens p)))
(let ((tt (ocaml-tok-type t)) (tv (ocaml-tok-value t)))
(cond
((= tt "eof") (set! done true))
((and (= tt "op") (= tv ";;")) (set! done true))
((and (= tt "keyword") (= tv "module")) (set! done true))
((and (= tt "keyword") (= tv "type")) (set! done true))
((and (= tt "keyword") (= tv "exception")) (set! done true))
((and (= tt "keyword") (= tv "open")) (set! done true))
((and (= tt "keyword") (= tv "include")) (set! done true))
((and (= tt "keyword") (= tv "and")) (set! done true))
((and (= tt "keyword") (= tv "let"))
(begin (set! d (+ d 1)) (set! p (+ p 1)) (scan)))
((and (= tt "keyword") (= tv "in"))
(cond
((= d 1) (begin (set! result true) (set! done true)))
(else
(begin (set! d (- d 1)) (set! p (+ p 1)) (scan)))))
(else (begin (set! p (+ p 1)) (scan)))))))))))
(scan)
result))))
;; Same as skip-to-boundary but treats inner `let` as the start
;; of a nested let..in (open depth) IF a matching `in` exists
;; before any decl boundary; otherwise stops.
(define
skip-let-rhs-boundary!
(fn ()
(let ((depth 0))
(begin
(define step
(fn ()
(cond
((>= idx tok-len) nil)
((= (ocaml-tok-type (peek-tok)) "eof") nil)
((and (= depth 0) (at-op? ";;")) nil)
((and (= depth 0) (at-kw? "module")) nil)
((and (= depth 0) (at-kw? "open")) nil)
((and (= depth 0) (at-kw? "include")) nil)
((and (= depth 0) (at-kw? "and")) nil)
((and (= depth 0) (at-kw? "type")) nil)
((and (= depth 0) (at-kw? "exception")) nil)
((and (= depth 0) (at-kw? "let"))
(cond
((has-matching-in?)
(begin (set! depth (+ depth 1)) (advance-tok!) (step)))
(else nil)))
((or (at-kw? "let") (at-kw? "begin") (at-kw? "struct")
(at-kw? "sig") (at-kw? "for") (at-kw? "while"))
(begin (set! depth (+ depth 1)) (advance-tok!) (step)))
((or (at-kw? "in") (at-kw? "end") (at-kw? "done"))
(begin
(when (> depth 0) (set! depth (- depth 1)))
(advance-tok!) (step)))
(else (begin (advance-tok!) (step))))))
(step)))))
(define
skip-to-boundary!
(fn ()
@@ -919,12 +995,6 @@
((and (= depth 0) (at-kw? "and")) nil)
((and (= depth 0) (at-kw? "type")) nil)
((and (= depth 0) (at-kw? "exception")) nil)
;; Track nested blocks that have explicit closing
;; tokens. let..in / begin..end / struct..end /
;; sig..end / for..done / while..done. `if`/`match`/
;; `try` don't have hard close tokens so we don't
;; track them — their bodies are bounded by the
;; surrounding expression structure.
((or (at-kw? "let") (at-kw? "begin") (at-kw? "struct")
(at-kw? "sig") (at-kw? "for") (at-kw? "while"))
(begin (set! depth (+ depth 1)) (advance-tok!) (step)))
@@ -968,7 +1038,7 @@
(consume! "op" "=")
(let ((expr-start (cur-pos)))
(begin
(skip-to-boundary!)
(skip-let-rhs-boundary!)
(let ((expr-src (slice src expr-start (cur-pos))))
(let ((expr (ocaml-parse expr-src)))
(append! bindings (list nm ps expr))))))))))