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ocaml: phase 5.1 calc.ml baseline (11/11 pass) + inline let-rec-and parser fix
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Recursive-descent calculator parses '(1 + 2) * 3 + 4' = 13. Two parser
bugs fixed:

1. parse-let now handles inline 'let rec a () = ... and b () = ... in
   body' via new (:let-rec-mut BINDINGS BODY) and (:let-mut BINDINGS
   BODY) AST shapes; eval handles both.

2. has-matching-in? lookahead no longer stops at 'and' — 'and' is
   internal to let-rec, not a decl boundary. Without this fix, the
   inner 'let rec a () = ... and b () = ...' inside a let-decl rhs
   would have been treated as the start of a new top-level decl.

Baseline exercises mutually-recursive functions, while-loops, ref-cell
imperative parsing, and ADT-based AST construction.
This commit is contained in:
giles
2026-05-08 16:53:44 +00:00
parent ecdd90345e
commit ffa74399fd
5 changed files with 170 additions and 28 deletions
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62
lib/ocaml/parser.sx
View File

@@ -666,36 +666,43 @@
(let ((body (parse-expr))) (list :fun params body))))))
(define
parse-let
(fn
()
(let
((reccy false))
(fn ()
(let ((reccy false) (bindings (list)))
(begin
(when
(at-kw? "rec")
(when (at-kw? "rec")
(begin (advance-tok!) (set! reccy true)))
(let
((name (ocaml-tok-value (consume! "ident" nil)))
(params (list)))
(begin
(define
collect-params
(fn ()
(let ((nm (try-consume-param!)))
(when (not (= nm nil))
(begin (append! params nm) (collect-params))))))
(collect-params)
(consume! "op" "=")
(let
((rhs (parse-expr)))
(define parse-one!
(fn ()
(let ((nm (ocaml-tok-value (consume! "ident" nil)))
(ps (list)))
(begin
(consume! "keyword" "in")
(let
((body (parse-expr)))
(if
reccy
(list :let-rec name params rhs body)
(list :let name params rhs body)))))))))))
(define collect-params
(fn ()
(let ((p (try-consume-param!)))
(when (not (= p nil))
(begin (append! ps p) (collect-params))))))
(collect-params)
(consume! "op" "=")
(let ((rhs (parse-expr)))
(append! bindings (list nm ps rhs)))))))
(parse-one!)
(define more
(fn ()
(when (at-kw? "and")
(begin (advance-tok!) (parse-one!) (more)))))
(more)
(consume! "keyword" "in")
(let ((body (parse-expr)))
(cond
((= (len bindings) 1)
(let ((b (first bindings)))
(if reccy
(list :let-rec (nth b 0) (nth b 1) (nth b 2) body)
(list :let (nth b 0) (nth b 1) (nth b 2) body))))
(else
(if reccy
(list :let-rec-mut bindings body)
(list :let-mut bindings body)))))))))
(define
parse-if
(fn
@@ -975,7 +982,6 @@
((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"))