From 0e28399b120778e07bdd02921d42597e00648e5b Mon Sep 17 00:00:00 2001
From: shivers <shivers>
Date: Fri, 28 Mar 1997 20:55:23 +0000
Subject: [PATCH] Changed regexp-substring so that unmatched submatches return
 #f instead of raising an error.

---
 scsh/re.scm | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/scsh/re.scm b/scsh/re.scm
index 647800e..7a35080 100644
--- a/scsh/re.scm
+++ b/scsh/re.scm
@@ -26,12 +26,9 @@
 (define (match:substring match . maybe-index)
   (let* ((i (:optional maybe-index 0))
 	 (start (vector-ref (regexp-match:start match) i)))
-    (if start
-	(substring (regexp-match:string match)
-		   start
-		   (vector-ref (regexp-match:end match) i))
-	(error match:substring "No sub-match found." match i))))
-
+    (and start (substring (regexp-match:string match)
+			  start
+			  (vector-ref (regexp-match:end match) i)))))
 
 ;;; Compiling regexps
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;