Re: Regular expression libraries

[Eli Zaretskii <eliz@gnu.org>]

> From: Clément Pit--Claudel <clement.pit@gmail.com>
> Date: Fri, 16 Dec 2016 15:06:13 -0500
> Cc: emacs-devel@gnu.org
> 
> Eli started listing things that we would need from an external library before we could move to it.  AFAICT, there is:
> 
> * Support for searching a gap buffer (essentially two strings).
> * Support for Emacs' internal utf-8 based encoding
> * Support for Emacs' regexp syntax (though we could imagine writing a translator)
> * Support for Emacs' syntax properties, and Emacs-specific extensions like matching the position of the point, etc.
> 
> An I missing anything else? Which ones of these things does gnulib already have?

 * Support for custom functions, independent of the current locale,
   that implement [:alpha:], [:print:], iswupper, etc.
 * Support for Emacs-specific character classes, like [:multibyte:]
   and [:unibyte:]
 * Support for Emacs character categories
 * Support for quitting in the middle of a regex operation
 * Support for treating a single blank as standing for any stretch of
   whitespace

Basically, search for "ifdef emacs", and you will find all the
Emacs-specific features we use.