From b34001408ffa208e2a56ed2f3c9bdf7ebc84efd9 Mon Sep 17 00:00:00 2001
From: Kevin Ryde <user42@zip.com.au>
Date: Mon, 6 Dec 2004 00:40:07 +0000
Subject: [PATCH] (break): Change to a tail-recursive form.

---
 srfi/srfi-1.scm | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/srfi/srfi-1.scm b/srfi/srfi-1.scm
index e83a0c0bd..5fb0bf07a 100644
--- a/srfi/srfi-1.scm
+++ b/srfi/srfi-1.scm
@@ -818,12 +818,11 @@
   (span pred list))			; XXX:optimize
 
 (define (break pred clist)
-  (if (null? clist)
-    (values '() '())
-    (if (pred (car clist))
-      (values '() clist)
-      (receive (first last) (break pred (cdr clist))
-	       (values (cons (car clist) first) last)))))
+  (let lp ((clist clist) (rl '()))
+    (if (or (null? clist)
+	    (pred (car clist)))
+	(values (reverse! rl) clist)
+	(lp (cdr clist) (cons (car clist) rl)))))
 
 (define (break! pred list)
   (break pred list))			; XXX:optimize