RE: [External] : Regexp for matching (defun lines

[Heime <heimeborgia@protonmail.com>]

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On Thursday, August 1st, 2024 at 3:34 PM, Drew Adams <drew.adams@oracle.com> wrote:

> > > > > > > (concat
> > > > > > > "^\\s-("
> > > > > > > (regexp-opt...)
> > > > > > > t)
> > > > > > > "\\s-+\\(\\(\\sw\\|\\s_\\)+\\)")
> > > > > > 
> > > > > > I see that you use "\\sw". What is the advantage verses
> > > > > > "[[:alnum:]-
> > > > > > _]"
> > > > > 
> > > > > No special advantage. You can include any other
> > > > > chars you want, so you can pick up, e.g.,
> > > > > 
> > > > > (defun foo!@$%^&*+={}/:42<>? ()
> > > > > (message "Hello"))
> > > > > 
> > > > > Perfectly legitimate, and none of those chars
> > > > > even require escaping.
> > > > 
> > > > Meaning that \\sw is superior to [[:alnum:]-_], right ?
> > > 
> > > No.
> > > 
> > > \\sw means word-char syntax.
> > > [[:alnum:]-_] means alphanumeric- or symbol-char syntax.
> > 
> > \sw is equivalent to "[:word:]", that includes digits. And [:alnum:]
> > is alphabetic and numeric. What is the difference ?
> 
> 
> https://www.gnu.org/software/emacs/manual/html_node/elisp/Char-Classes.html
> 
> says:
> 
> ‘[:alnum:]’
> This matches any letter or digit. For multibyte characters, it
> matches characters whose Unicode ‘general-category’ property (*note
> Character Properties::) indicates they are alphabetic or decimal
> number characters.

> The same is not said for [:word:].

I thought that alphabetic and words constitute the same characters.
[:word:] also matches accented letter (e.g., in French, Spanish, Icelandic).
It is difficult to know what is actually defined these days.