Bug using "-" last in `skip-chars-forward'

Bug using "-" last in `skip-chars-forward'

[Martin Stjernholm]

The following bug exists both in Emacs 21.3 and XEmacs 21.4 (patch
14):

1.  Start (X)Emacs with -q -no-site-file.
2.  Create a buffer and type "-" in it.
3.  Go back to the beginning of the buffer.
4.  Evaluate (skip-chars-forward "y-").

The point does not move, whereas I expected it to skip forward past
the "-". That since a "-" last in a normal regexp character
alternative is not special. `skip-chars-forward' does not use quite
the same syntax, but according to the manual that detail should still
be the same.

Furthermore, if "-" in the buffer is replaced with "y", it still
doesn't skip forward past it.

I.e. when the string to `skip-chars-forward' or `skip-chars-backward'
ends with a "-" that doesn't also start it, both it and the preceding
character are ignored.

Re: Bug using "-" last in `skip-chars-forward'

[Kevin Rodgers]

Martin Stjernholm wrote:

> The following bug exists both in Emacs 21.3 and XEmacs 21.4 (patch
> 14):
> 
> 1.  Start (X)Emacs with -q -no-site-file.
> 2.  Create a buffer and type "-" in it.
> 3.  Go back to the beginning of the buffer.
> 4.  Evaluate (skip-chars-forward "y-").
> 
> The point does not move, whereas I expected it to skip forward past
> the "-". That since a "-" last in a normal regexp character
> alternative is not special. `skip-chars-forward' does not use quite
> the same syntax, but according to the manual that detail should still
> be the same.
> 
> Furthermore, if "-" in the buffer is replaced with "y", it still
> doesn't skip forward past it.
> 
> I.e. when the string to `skip-chars-forward' or `skip-chars-backward'
> ends with a "-" that doesn't also start it, both it and the preceding
> character are ignored.

I'm not sure this is a bug.  The doc string for skip-chars-forward says:


| 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).

(skip-chars-forward "y\\-") works, as does (skip-chars-forward "y---").

Since "y-" is not a range, I don't think the parenthetical remark in
the doc string is relevant.

-- 
Kevin Rodgers