Re: display-buffer-alist simplifications

[martin rudalics]

> Here are the difference I see:
> - use functions rather than a finite set of symbols.

Not really a difference because `display-buffer-alist' provides the
function specifier.

> - handle the FUNCTION or FUNCTIONS (i.e. the list of methods to use/try)
>   separately from the other arguments, i.e. separate the part which is
>   tried in sequence from the part that's handled as an alist.

Indeed.  These are strongly tied in `display-buffer-alist'.

>> So when an application sets the argument, people who want the old
>> behavior are overridden.  This means that such people can use
>> `message-mail' as before but any of their customizations affecting
>> `message-mail-other-window' or `message-mail-other-frame' are lost.
>
> Yes (unless message-mail-other-window keeps using the old let-binding
> horror, of course).

With customization I meant that so far they can make
`message-mail-other-window' use another frame by setting `pop-up-frames'
to t.  This won't be possible any more.

martin