16678.64845.425272.796078(a)cerise.nosuchdomain.co.uk mentioned this lacuna in passing. man/ChangeLog addition: 2005-02-23 Aidan Kehoe <kehoea(a)parhasard.net&gt; * lispref/searching.texi (Syntax of Regexps): Mention the \c and \C regular expression constructs; cross reference to the Category Table documentation. XEmacs Trunk source patch: Diff command: cvs -q diff -u Files affected: man/lispref/searching.texi Index: man/lispref/searching.texi =================================================================== RCS file: /pack/xemacscvs/XEmacs/xemacs/man/lispref/searching.texi,v retrieving revision 1.12 diff -u -u -r1.12 searching.texi --- man/lispref/searching.texi 2004/09/08 10:32:55 1.12 +++ man/lispref/searching.texi 2005/02/23 15:14:22 ＠＠ -516,6 +516,19 ＠＠ ＠item \S＠var{code} ＠cindex ＠samp{\S} in regexp matches any character whose syntax is not ＠var{code}. + +＠item \c＠var{category} +＠cindex ＠samp{\c} in regexp +matches any character in ＠var{category}. Only available under Mule, +categories, and category tables, are further described in ＠ref{Category +Tables}. They are a mechanism for constructing classes of characters +that can be local to a buffer, and that do not require complicated [] +expressions every time they are referenced. + +＠item \C＠var{category} +＠cindex ＠samp{\C} in regexp +matches any character outside ＠var{category}. ＠xref{Category Tables}, +again, and note that this is only available under Mule. ＠end table The following regular expression constructs match the empty string---that is, -- “I, for instance, am gung-ho about open source because my family is being held hostage in Rob Malda’s basement. But who fact-checks me, or Enderle, when we say something in public? No-one!” -- Danny O’Brien