(Regexp Search): Explain why forward and reverse regexp

search are not mirror images.

diff --git a/man/search.texi b/man/search.texi
index 67b61aeac072123788f35d9cb40ea5714139d9f5..532d58fb9d8465517336d91dc3acd90dd7aa23c5 100644 (file)
--- 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