[emacs-wiki-discuss] skip-chars-forward (was: Re: XEmacs and character classes)

[Vadim Nasardinov]

On Tuesday 21 December 2004 16:12, Carl Worth wrote:
> >   |(defun emacs-wiki-insert-anchor (anchor)
> >   |  "Insert an anchor, either around the word at point, or within a tag."
> >   |  (skip-chars-forward "[:space:]")
> > 
> > Since my Emacs doesn't seem to understand the character class
> > [:space:],
> 
> I'm confused about these threads mentioning the problems with
> character classes.
> 
> I wouldn't expect "[:space:]" to get provide the desired effect. But
> is "[[:space:]]" not supported universally in emacs?

Ah, yes, you are right.  The "[[:space:]]" regexp works just fine.

"C-h f skip-chars-forward" has this to say,

    skip-chars-forward is a built-in function.
    (skip-chars-forward STRING &optional LIM)

    Move point forward, stopping before a char not in STRING, or at
    pos LIM.  STRING is like the inside of a `[...]' in a regular
    expression except that `]' is never special and `\' quotes `^',
    `-' or `\' (but not as the end of a range; quoting is never needed
    there).
    Thus, with arg "a-zA-Z", this skips letters stopping before first
    nonletter.  With arg "^a-zA-Z", skips nonletters stopping before
    first letter.  Returns the distance traveled, either zero or
    positive.

So, in theory, it sounds like doing something like this

  (skip-chars-forward "baz")

means, Skip characters matching the regexp "[baz]".

By the same token,

  (skip-chars-forward "[:space:]")

can be expected to mean, Skip characters matching the regexp "[[:space:]]".

Except that it doesn't seem to work that way.  Not for me, at least.


Thanks,
Vadim