bug#17130: 24.4.50; Deficient Unicode case folding

[Eli Zaretskii]

> From: Nathan Trapuzzano <nbtrap@nbtrap.com>
> Cc: 17130@debbugs.gnu.org
> Date: Sat, 29 Mar 2014 08:37:35 -0400
> 
> Reading through the manual section on case tables, it seems that this
> could be supported via the extra "canonicalize" slot:
> 
>     CANONICALIZE
>       The canonicalize table maps all of a set of case-related
>       characters into a particular member of that set.

Not efficiently, no.  E.g., how will you find ς from σ, using this
method?

Besides, don't we also need to know that ς can only be present at the
end of a word?

Or maybe I'm misunderstanding what you meant?

> If this isn't already used for Unicode case folding, what _is_ it used
> for?

It is used for case-insensitive regexp matching, see search.c.