(Regexp Search): Explain why forward and reverse regexp

search are not mirror images.

2 files changed, 17 insertions, 0 deletions

diff --git a/man/ChangeLog b/man/ChangeLog
index 32836432ddf..a3447fd1d95 100644
--- a/man/ChangeLog
+++ b/man/ChangeLog
@@ -1,3 +1,13 @@
+2006-12-23  Richard Stallman  <rms@gnu.org>
+
+        * search.texi (Regexp Search): Explain why forward and reverse regexp
+        search are not mirror images.
+
+2006-12-22  Kevin Ryde  <user42@zip.com.au>
+
+        * cl.texi (Sorting Sequences): Typo in sort*, example showed plain
+        "sort" instead of "sort*".
+
 2006-12-19  Richard Stallman  <rms@gnu.org>
 
         * calc.texi (History and Acknowledgements): Recognize that Emacs
diff --git a/man/search.texi b/man/search.texi
index 67b61aeac07..532d58fb9d8 100644
--- a/man/search.texi
+++ b/man/search.texi
@@ -488,6 +488,13 @@ search can make the cursor move back and start again.  For example, if
 you have searched for @samp{foo} and you add @samp{\|bar}, the cursor
 backs up in case the first @samp{bar} precedes the first @samp{foo}.
 
+  Forward and backward regexp search are not symmetrical, because
+regexp matching in Emacs always operates forward, starting with the
+beginning of the regexp.  Thus, forward regexp search scans forward,
+trying a forward match at each possible starting position.  Backward
+regexp search scans backward, trying a forward match at each possible
+starting position.  These search methods are not mirror images.
+
 @findex re-search-forward
 @findex re-search-backward
   Nonincremental search for a regexp is done by the functions