Re: goof in small function where???

[ken]

On 07/22/2014 06:02 AM Michael Heerdegen wrote:
> ken <gebser@mousecar.com> writes:
>
> > (defun file-name-into-kill-buffer ()
> > "Put path/filename of current buffer onto kill-ring so to paste
> > into an X application.  Also display it in minibuffer."
> > (interactive)
> >       (let ((str (buffer-file-name)))
> >         (and str
> >              (kill-new str)
> >              (message "Copied filename %s to kill ring" str)))
> > )
>
> This doesn't work when `kill-new' returns nil, which happens when
> `interprogram-cut-function' is nil (which is the default).  Note that
> the doc of `kill-new' doesn't say anything about the return value, it
> can be anything.
>
> Ergo: the `and' should better be a `when'.

Yes!  That fixed it!!  Thanks very much.

I'm vaguely understanding that the 'and' doesn't evaluate '(message...' 
when '(kill-new...' returns nil and, since its return value is 
undefined, it can do on occasion.  Replacing 'and' with 'when' ensures 
'(message...' is evaluated regardless of what '(kill-new...' returns.

Is that about right?


Thanks again.