fix #17668, deprecation for for ( ... )

NEWS.md

@@ -98,6 +98,9 @@ Language changes
  * Dictionary comprehension syntax `[ a=>b for x in y ]` is deprecated.
  Use `Dict(a=>b for x in y)` instead ([#16510]).
 
+ * Parentheses are no longer allowed around iteration specifications, e.g.
+ `for (i = 1:n)` ([#17668]).
+
 Library improvements
 --------------------
 

src/julia-parser.scm

@@ -1415,7 +1415,8 @@
 
 ;; as above, but allows both "i=r" and "i in r"
 (define (parse-iteration-spec s)
- (let* ((lhs (parse-pipes s))
+ (let* ((paren? (eqv? (require-token s) #\())
+ (lhs (parse-pipes s))
  (t (peek-token s)))
  (cond ((memq t '(= in ∈))
  (take-token s)
@@ -1428,6 +1429,13 @@
  `(= ,lhs ,rhs)))
  ((and (eq? lhs ':) (closing-token? t))
  ':)
+ ((and paren? (length= lhs 4) (eq? (car lhs) 'call)
+ (memq (cadr lhs) '(in ∈)))
+ (syntax-deprecation s "for (...)" "for ...")
+ `(= ,@(cddr lhs)))
+ ((and paren? (length= lhs 3) (eq? (car lhs) '=))
+ (syntax-deprecation s "for (...)" "for ...")
+ lhs)
  (else (error "invalid iteration specification")))))
 
 (define (parse-comma-separated-iters s)