bug#19461: 25.0.50; doc of `display-buffer-*' functions that take ALIST arg

[Michael Heerdegen]

martin rudalics <rudalics@gmx.at> writes:

> 'display-buffer' calls it ACTION argument.  A problem with this is
> that so far we do not specify what a "valid" action function is.

Maybe that should be done.  Would there be more to say than that an
action function should either return a window (success) or nil (fail),
and respect the specified specifications in the ALIST, and what actions
are predefined?

> A possible text would be:
>
> "This is an action function for buffer display.  It should be called
> only by 'display-buffer' or a function directly or indirectly called
> by the latter."
>
> Or with a reference to the Elisp manual:
>
> "This is an action function for buffer display, see Info node `(elisp)
> Buffer Display Action Functions'.  It should be called only by
> 'display-buffer' or a function directly or indirectly called by the
> latter."

Sounds ok.  AFAIU this covers defining new actions by using existing
ones, like in

(defun my-display-buffer-pop-up-frame-dedicated (b alist)
  (let ((w (display-buffer-pop-up-frame b alist)))
    (when (windowp w) (set-window-dedicated-p w t))
    w))

right?

Michael.