Re: Regexp capturing unicode characters

[Heime <heimeborgia@protonmail.com>]

On Friday, August 2nd, 2024 at 12:10 AM, Eli Zaretskii <eliz@gnu.org> wrote:

> > Date: Thu, 01 Aug 2024 11:26:40 +0000
> > From: Heime heimeborgia@protonmail.com
> > Cc: help-gnu-emacs@gnu.org
> > 
> > On Thursday, August 1st, 2024 at 5:15 PM, Eli Zaretskii eliz@gnu.org wrote:
> > 
> > > > Date: Wed, 31 Jul 2024 21:24:46 +0000
> > > > From: Heime heimeborgia@protonmail.com
> > > > 
> > > > I am using unicode characters in my elisp code (e.g. foreign language symbols in icelandic
> > > > and spanish).
> > > > 
> > > > Is the regexp [[:word:]] appropriate to capture them ?
> > > 
> > > No. [[:word:]] matches characters that have the word syntax, so which
> > > characters match depends on the major mode. My suggestion is to use
> > > either [[:alnum:]] or [[:alpha:]] instead, depending on whether you
> > > want or don't want to match digit characters.
> > > 
> > > The meaning of each character class is documented in the "Char
> > > Classes" node of the ELisp Reference manual, I suggest to read it and
> > > choose the most appropriate one for your needs.
> > 
> > It is difficult to determine from a character class, the actual character.
> 
> Why do you need that? Don't you know which characters you'd like to
> match?

No, because language insertion in emacs depends upon the user.  But I want 
to match foreign language characters mostly.
 
> > Is there a way to show the characters that are members of each class ?
> 
> No, but you can check each character whether it matches a class.

What is the function name for doing that ?  Can one scan the buffer
and list the matched character classes ?
 
> > Thought that [:multibyte:] captured the unicode characters. Bet even when
> > I applied (set-buffer-multibyte t) to the buffer, I did not get matches.
> 
> Don't use [:multibyte:], it is hardly ever the right thing nowadays.

Can we update the manual with useful information such as with [:multibyte:] please.
 
> > Does [:word:] mean word in the english language only ?
> 
> 
> No, it means characters that have the word syntax. IOW, which
> character match depends on the major mode's syntax table. If you are
> classifying characters from human-readable text, [:word:] is not the
> right thing to use.

Can one show the syntax table ?  For me it is just word syntax table does 
not give me enough information.  Perhaps give more explanation in the manual.