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

[Drew Adams <drew.adams@oracle.com>]

> > > > > > (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:].