Re: CVS directories in completion-ignored-extensions

[Miles Bader <miles@gnu.org>]

Richard Stallman <rms@gnu.org> writes:
> > I've always thought it would be nice, instead of having multiple
> > variables each of which contain a different types of entry, to have
> > something like `completion-ignored-names', where each element could
> > be either: a string (which is matched using just `equal'), or a list
> > like (regexp REGEXP), which the matcher would treat accordingly.
> 
> That is a good idea.

Ok, how about something like:

   (defun string-matcher-member (string matcher)
     "Return non-nil if STRING is matched by the `string matcher' MATCHER.
   MATCHER should be a list, where each element is either a string,
   which will be compared with STRING using `equal', or a cons of the
   form (regexp REGEXP), in which case REGEXP will be compared with
   STRING using `string-match'.  The actual return value is the first
   element of MATCHER that matches."
     (let (test)
       (while matcher
         (setq test (pop matcher))
         (if (cond ((stringp test) 
                    (equal string test))
                   ((eq (car-safe test) 'regexp)
                    (if (consp (cdr test))
                        (string-match (car-safe (cdr-safe test)) string)
                      (string-match (cdr-safe test) string))))
             (setq matcher nil)
           (setq test nil)))
       test))

The name `string-matcher-member' is kind of ugly, but at least it
seems fairly clear; maybe someone can think of a better name.

The nice thing is that this is basically backward-compatible with existing
lists of strings that are matched exactly, so perhaps some of them could
be retro-fitted accordingly (e.g.  `dabbrev-ignored-buffer-names').

[`special-display-buffer-names' is similar (it has a corresponding
`special-display-regexps'), but because it itself gives special treatment
to list members that are cons-cells, doesn't fit exactly into such a
scheme (maybe it could be finessed, I don't know).]

-Miles
-- 
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`All the past could be forgiven.'   [NYT]