Re: Char-folding: how can we implement matching multiple characters as a single "thing"?

[Eli Zaretskii <eliz@gnu.org>]

> From: Clément Pit--Claudel <clement.pit@gmail.com>
> Date: Mon, 30 Nov 2015 17:49:35 +0100
> 
> * Extend the C-level implementation of regular expressions to make character-folding a capability of the C engine, allowing for succinct regexps + a flag.
> * Add a new backslash to regular expressions for matching char-folded characters (custom character categories almost already allow for this, so the implementation would probably be similar).

The correct implementation for character folding is the same as for
case-folding: on the C level of the search.c routines.  This was
discussed back when this feature was in the design phase.  However,
the undertaking of coding this in search.c was too complex, so we
decided to go with the current implementation in Lisp and live with
its limitations for the time being.

Volunteers are welcome to work on the ultimate solution, which should
indeed include normalization of both the search string and the
buffer/string text that is searched.

Thanks.