add `from/stop-before`

brag/brag/brag.scrbl

@@ -1053,5 +1053,9 @@ characters.}
 
 A string that is bounded by @racket[open] and @racket[close]. Matching is non-greedy (meaning, it stops at the first occurence of @racket[close]). The resulting lexeme includes @racket[open] and @racket[close]. To remove them, see @racket[trim-ends].}
 
+@defform[(from/stop-before open close)]{
+
+Like @racket[from/to], a string that is bounded by @racket[open] and @racket[close], except that @racket[close] is not included in the resulting lexeme. Matching is non-greedy (meaning, it stops at the first occurence of @racket[close]).}
+
 
 @close-eval[my-eval]

brag/brag/support.rkt

@@ -92,8 +92,16 @@
   (λ(stx)
     (syntax-case stx ()
       [(_ OPEN CLOSE)
+       ;; (:seq any-string CLOSE any-string) pattern makes it non-greedy
        #'(:seq OPEN (complement (:seq any-string CLOSE any-string)) CLOSE)])))
 
+(provide from/stop-before)
+(define-lex-trans from/stop-before
+  (λ(stx)
+    (syntax-case stx ()
+      [(_ OPEN CLOSE)
+       #'(:seq OPEN (:* (:~ CLOSE)))])))
+
 (provide uc+lc)
 (define-lex-trans uc+lc
   (λ(stx)