Re: count matches in string, not region?

[Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

> Anyway as you see the 4th line doesn't look
> good, instead of moving the point one would
> like to invoke the/a count function with the
> already-fetched isbn-as argument.
>
> So is there a count-matches-in-string or
> something to that extent anywhere, that you
> are aware of?

Problem solved with `replace-regexp-in-string'.

Can still be useful to count matches in
a string, I guess...

Yank it in a temporary buffer and then use
region there is perhaps a poor man's solution...

(defun check-isbn-at-point ()
  "Compute and echo the check digit from the ISBN at point."
  (interactive)
  (let*((isbn-string (thing-at-point 'symbol t))
        (digits-only (replace-regexp-in-string "[^0-9]" "" isbn-string))
        (num-digits  (length digits-only))
        (check-digit (if (> num-digits 10)
                         (checksum-isbn-13 digits-only)
                       (checksum-isbn-10 digits-only) )))
    (message "check digit: %s" check-digit)
    ))
(defalias 'ciap #'check-isbn-at-point)

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