Re: installing emacs and X11 on OS X

[Eli Zaretskii <eliz@is.elta.co.il>]

On 28 Oct 2002, Thomas F. Burdick wrote:

> > People will abuse less if they have less opportunities for abuse.
> 
> I guess so long as a new facility for determining what environment
> you're working in, is introduced, this is a fine decision.  I imagine,
> though, that any time you give people the ability to ask what
> look-and-feel environment they're operating in, they'll abuse it to
> test for display features.

There's a difference.  Abuse because there's no alternative means to do 
what you want is more likely and more justified than if the means to do 
it right do exist.

> What's there is good, but more is needed.  I guess that possiblity is
> part of why window-system was depricated, instead of removed, huh?

It wasn't removed simply because such abrupt changes are bad practice, 
they hurt back-compatibility too much.

> I think what's needed is the ability to ask run-time questions like
> the above.  So either a look-and-feel-p predicate, or a series of
> display-look&feel-*-p predicates, so I could write code like this:
> 
>   (when (display-look&feel-carbon-p)
>     (setup-carbon-look&feel))

Yes, this sounds to me like a good idea.  Please suggest this on 
emacs-devel.

>   (when (display-look&feel-x11-p)
>     ;; Things like mouse-2 for paste
>     (setup-x11-look&feel))
> 
>   (when (display-look&feel-mswin-p)
>     ;; No mouse-2 for pasting, use cua-mode instead
>     (setup-mswin-look&feel))

This is IMHO not such a good idea.  If there's a need to know something 
about the functionality of mouse-2, or about the lack thereof, there 
should be a specific predicate for that.  The very reason that you needed 
to put a comment explaining why X11 differs from MS-Windows is an 
evidence that the predicate is going to be a grabbag of indicators for 
support of several unrelated features, features that are not explicitly 
obvious from the predicate name.  If we want to dostinguish between 
2-button and 3-button Emacs, let's do that explicitly, let's not hide 
behind some look and feel.