Re: Display-local variables (Re: It is time for a feature freeze)

[Lőrentey Károly]

Kim F. Storm <address@hidden> writes:
>> I am now convinced that display-local variables are not really
>> necessary.  What about making displays first-level Lisp objects?  Are
>> there any objections against that?
>
> Where is this needed ?

First, it would make it easy to implement support for having more than
one display on the same device.  I'd like to be able to have more than
one emacsclient tty sessions on the same terminal.  The only problem is
that Lisp code can not currently distinguish between two displays that
are on the same device.  I think exposing the display list to Lisp
would solve that problem nicely.

Plus, having a display type would make it easier in general to
manipulate displays from Lisp code. E.g. for checking that two frames
are on the same display, I'd like to simply say:

        (eq (frame-display a) (frame-display b))

Do you know an easy way to provide this functionality without
Lisp-level display types?  (Well, I guess I could assign an id number
for each display, but that does not sound like the Emacs Way.
For example, handling deleted displays would be hard to do right.)

-- 
Károly