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Re: reducing defface redundancy
From: |
Miles Bader |
Subject: |
Re: reducing defface redundancy |
Date: |
22 Apr 2002 09:28:07 +0900 |
Richard Stallman <address@hidden> writes:
> The basic idea is to allow using a lisp vector ([...]) as a kind of `or'
> expression in the attribute part of a defface clause.
>
> Your proposal makes a number of other changes;
> is this the best way to do all of them?
>
> I don't see how an "or" construct would be a kind of clause:
>
> CLAUSE ::= ATTRIBUTE
> | (TESTS CLAUSE...) ; traditional top-level style
> | [SPECS ...] ; `or' vector style
>
> Shouldn't it be a kind of TEST instead?
Well, it's not really an `or' in the exact same sense as a typical or
function used in lisp, say.
It's more like the alternatives used for a prolog rule or something, it
tries each element in order until it finds out that is `supportable'.
So a user can just write:
[ALTERNATIVE1 ALTERNATIVE2 ... DEFAULT]
and the lisp code will effectively say `does the display support all
the attributes ALTERNATIVE1? If so, lets use that. If not, does the
display support all the attributes in ALTERNATIVE2? ...' etc.
I think this often _exactly_ what people are actually _thinking_ when
they design a defface spec (they want a certain effect for the face, and
can think of several physical appearances that might convey it).
[Note that the I've suggested adding the `capability testing' as a
traditional TEST as well, in case someone wants to use that instead.]
I do think, BTW, that the ability to write non-conditional defface
specs with this grammar is a benefit, since I always get annoyed that
I've got to stick in the ((t ...)) crap even when I know I don't need
any tests... :-)
-Miles
--
Would you like fries with that?
- Re: reducing defface redundancy, (continued)
- Re: reducing defface redundancy, Richard Stallman, 2002/04/22
- Re: reducing defface redundancy, Richard Stallman, 2002/04/22
- Re: reducing defface redundancy, Miles Bader, 2002/04/22
- Re: reducing defface redundancy, Richard Stallman, 2002/04/22
- Re: reducing defface redundancy, Miles Bader, 2002/04/22
- Re: reducing defface redundancy, Richard Stallman, 2002/04/24
- Re: reducing defface redundancy, Miles Bader, 2002/04/24
- Re: reducing defface redundancy, Per Abrahamsen, 2002/04/25
- Re: reducing defface redundancy, Richard Stallman, 2002/04/25
Re: reducing defface redundancy, Richard Stallman, 2002/04/21
- Re: reducing defface redundancy,
Miles Bader <=