From 5b17f850cd17bae5aee32bc2a7a000cfb6b039ea Mon Sep 17 00:00:00 2001
From: Charles Haley <>
Date: Tue, 7 Jun 2011 15:46:05 +0100
Subject: [PATCH] Add discussion about doubled backslashes for escaping chars
 in search query regular expressions

---
 src/calibre/manual/gui.rst | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/calibre/manual/gui.rst b/src/calibre/manual/gui.rst
index 752c9c4881..f4b04f6e9d 100644
--- a/src/calibre/manual/gui.rst
+++ b/src/calibre/manual/gui.rst
@@ -326,8 +326,9 @@ Two other kinds of searches are available: equality search and search using regu
 Equality searches are indicated by prefixing the search string with an equals sign (=). For example, the query
 ``tag:"=science"`` will match "science", but not "science fiction" or "hard science". Regular expression searches are
 indicated by prefixing the search string with a tilde (~). Any python-compatible regular expression can
-be used. Regular expression searches are contains searches unless the expression contains anchors.
-Should you need to search for a string with a leading equals or tilde, prefix the string with a backslash.
+be used. Note that backslashes use to escape special characters in reqular expressions must be doubled, because single backslashes will be removed during query parsing. For example, to match a literal parenthesis, you must enter ``\\(``. Regular expression searches are contains searches unless the expression contains anchors. 
+
+Should you need to search for a string with a leading equals or tilde, prefix the string with a backslash. 
 
 Enclose search strings with quotes (") if the string contains parenthesis or spaces. For example, to search
 for the tag ``Science Fiction``, you would need to search for ``tag:"=science fiction"``. If you search for