From: Eli Zaretskii <eliz@gnu.org>
To: Paul Eggert <eggert@cs.ucla.edu>
Cc: stephen@xemacs.org, dmantipov@yandex.ru,
monnier@iro.umontreal.ca, emacs-devel@gnu.org
Subject: Re: ptrdiff_t misuse
Date: Fri, 06 Jul 2012 18:43:37 +0300 [thread overview]
Message-ID: <834npk3nfa.fsf@gnu.org> (raw)
In-Reply-To: <4FF6FCB0.8080400@cs.ucla.edu>
> Date: Fri, 06 Jul 2012 07:56:48 -0700
> From: Paul Eggert <eggert@cs.ucla.edu>
> CC: "Stephen J. Turnbull" <stephen@xemacs.org>, dmantipov@yandex.ru,
> monnier@iro.umontreal.ca, emacs-devel@gnu.org
>
> On 07/06/2012 04:01 AM, Eli Zaretskii wrote:
> > It is easy enough to explain that EMACS_POS is used for Lisp integers
> > that express buffer and string positions, and EMACS_INT for any other
> > Lisp integer values.
>
> But not every use of ptrdiff_t is for buffer and string positions.
> Bitmap table sizes, for example.
Do they really need to be large?
> EMACS_INT for Lisp integer values
> EMACS_POS for buffer and string positions
> ptrdiff_t for other large memory-related numbers
>
> and at that point, we'll need to teach Emacs hackers about
> ptrdiff_t anyway.
Not if the objects that use ptrdiff_t are many. And perhaps we don't
need ptrdiff_t at all, if the size doesn't need to be large.
> An argument for EMACS_POS is that it clearly identifies an
> integer as being used for a buffer or a string position, as
> having some other ptrdiff_t-like use. But in that case shouldn't
> we also distinguish between buffer positions and string positions?
What for? they span the same range of values.
> And distinguish between character and byte counts, in both cases?
What for? they span the same range of values. And the fact that it's
a byte position is usually clearly stated in the name of the variable
itself.
> EMACS_INT for Lisp integer values
> EMACS_BUFCPOS for buffer char positions
> EMACS_BUFBPOS for buffer byte positions
> EMACS_STRCPOS for string char positions
> EMACS_STRBPOS for string byte positions
> ptrdiff_t for other large memory-related numbers
>
> This question answers itself, I think -- the extra complexity
> isn't worth it
Only if you take the argument towards the absurd.
next prev parent reply other threads:[~2012-07-06 15:43 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-29 13:20 (unknown) Eli Zaretskii
2012-06-29 14:18 ` ptrdiff_t misuse [was :Re: (empty)] Dmitry Antipov
2012-06-29 17:07 ` Stefan Monnier
2012-06-30 7:13 ` Paul Eggert
2012-06-30 7:27 ` Eli Zaretskii
2012-06-30 13:12 ` Paul Eggert
2012-06-30 14:23 ` Stefan Monnier
2012-06-30 12:07 ` Stefan Monnier
2012-06-30 13:14 ` Paul Eggert
2012-06-30 14:23 ` Stefan Monnier
2012-07-04 6:25 ` Paul Eggert
2012-07-04 16:39 ` Eli Zaretskii
2012-07-04 18:19 ` Paul Eggert
2012-07-05 16:31 ` Eli Zaretskii
2012-07-05 19:34 ` Eli Zaretskii
2012-07-06 0:08 ` Paul Eggert
2012-07-06 6:43 ` Eli Zaretskii
2012-07-06 7:32 ` Paul Eggert
2012-07-06 8:34 ` ptrdiff_t misuse Eli Zaretskii
2012-07-06 14:51 ` Paul Eggert
2012-07-06 21:30 ` Stefan Monnier
2012-07-06 21:33 ` Samuel Bronson
2012-07-07 10:59 ` Stefan Monnier
2012-07-07 15:34 ` Paul Eggert
2012-07-06 8:46 ` Eli Zaretskii
2012-07-06 10:19 ` Stephen J. Turnbull
2012-07-06 11:01 ` Eli Zaretskii
2012-07-06 12:02 ` Stephen J. Turnbull
2012-07-06 13:37 ` Eli Zaretskii
2012-07-06 16:25 ` Stephen J. Turnbull
2012-07-06 14:56 ` Paul Eggert
2012-07-06 15:43 ` Eli Zaretskii [this message]
2012-07-06 15:56 ` Paul Eggert
2012-07-06 16:00 ` Eli Zaretskii
2012-07-06 16:42 ` Dmitry Antipov
2012-07-06 17:39 ` Paul Eggert
2012-07-07 1:31 ` Chong Yidong
2012-06-29 18:54 ` ptrdiff_t misuse [was :Re: (empty)] Eli Zaretskii
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