Re: Optional Arguments

[pietru]

> Sent: Monday, December 07, 2020 at 9:52 PM
> From: "Arthur Miller" <arthur.miller@live.com>
> To: "Michael Heerdegen" <michael_heerdegen@web.de>
> Cc: help-gnu-emacs@gnu.org
> Subject: Re: Optional Arguments
>
> Michael Heerdegen <michael_heerdegen@web.de> writes:
>
> > pietru@caramail.com writes:
> >
> >> Am getting an error with the following.
> >>
> >> (defun word-markers ()
> >>    (let ((ma mb)) <--

I see it now, the parenthesis was assigning to ma other than nil.
Thank you so very much.

> > You bind `ma' to the value of `mb'.  That's not what you want.
> Exactly; this is what I had in my scratch when I tested: I just didn't
> copy everything in previous answer:
>
> (defun word-markers ()
>   (let (ma mb)
>     (skip-chars-backward "[:alpha:]")
>     (setq ma (point))
>     (skip-chars-forward "[:alpha:]")
>     (setq mb (point))
>     (cons ma mb)))
>
> (defun test ()
>    (interactive)
>    (let ((deactivate-mark nil)
>          bounds ma mb)
>      (if (use-region-p)
>          (setq ma (region-beginning) mb (region-end))
>        (save-excursion
>          (setq bounds (word-markers))
>          (setq ma (car bounds))
>          (setq mb (cdr bounds))))
>    (message "Bounds: %s" (pp bounds))
>    (message "Region: [%s %s]" ma mb)
>    (message "Region-string: [%s]" (buffer-substring-no-properties ma mb))))
>
> (test)
>
> Tou should drop one parenthesis around ma and mb in your let
> expression. That will declare two variables and initialize them to nil both.
>
>