Fix bug: SIGSEGV when M-x occur matches 0 lines.

diff --git a/v7/src/edwin/occur.scm b/v7/src/edwin/occur.scm
index de7a2644de66215b4a7c79859b06295bdc30cf6a..5b37be930986bda17aedd6e8b50ffc6181ccd5d3 100644 (file)
--- a/v7/src/edwin/occur.scm
+++ b/v7/src/edwin/occur.scm
@@ -1,8 +1,9 @@
 #| -*-Scheme-*-
 
-$Id: occur.scm,v 1.10 2004/10/23 04:01:09 cph Exp $
+$Id: occur.scm,v 1.11 2005/01/17 20:03:55 cph Exp $
 
 Copyright 1992,1995,1997,2000,2003,2004 Massachusetts Institute of Technology
+Copyright 2005 Massachusetts Institute of Technology
 
 This file is part of MIT/GNU Scheme.
 
@@ -228,23 +229,25 @@ It serves as a menu to find any of the occurrences in this buffer.
            (reverse! occurrences))))))
 
 (define (format-occurrences occurrences nlines output)
-  (let loop
-      ((occurrences occurrences)
-       (prev-ls #f)
-       (line 1))
-    (let ((r (car occurrences))
-         (m (mark-right-inserting-copy output)))
-      (let ((ls (line-start (region-start r) 0)))
-       (let ((line (+ line (count-lines (or prev-ls (group-start ls)) ls))))
-         (format-occurrence ls (line-start (region-end r) 0)
-                            line nlines
-                            output)
-         (region-put! m output 'OCCURRENCE r)
-         (if (pair? (cdr occurrences))
-             (begin
-               (if (not (= nlines 0))
-                   (insert-string "--------\n" output))
-               (loop (cdr occurrences) ls line))))))))
+  (if (pair? occurrences)
+      (let loop
+         ((occurrences occurrences)
+          (prev-ls #f)
+          (line 1))
+       (let ((r (car occurrences))
+             (m (mark-right-inserting-copy output)))
+         (let ((ls (line-start (region-start r) 0)))
+           (let ((line
+                  (+ line (count-lines (or prev-ls (group-start ls)) ls))))
+             (format-occurrence ls (line-start (region-end r) 0)
+                                line nlines
+                                output)
+             (region-put! m output 'OCCURRENCE r)
+             (if (pair? (cdr occurrences))
+                 (begin
+                   (if (not (= nlines 0))
+                       (insert-string "--------\n" output))
+                   (loop (cdr occurrences) ls line)))))))))
 
 (define (format-occurrence rs re line nlines output)
   (let ((empty "       "))