EARRAYSIZE

EARRAYSIZE

[Eli Zaretskii]

  +/* Find number of elements in array */
  +#define EARRAYSIZE(arr) (sizeof (arr) / sizeof ((arr)[0]))

I find the name of this macro to be unfortunate: what it returns is
not "size" in the accepted meaning of that word.

How about ALEN, or ARRAYELTS instead?

Re: EARRAYSIZE

[Daniel Colascione]

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On 04/03/2014 12:30 PM, Eli Zaretskii wrote:
>   +/* Find number of elements in array */
>   +#define EARRAYSIZE(arr) (sizeof (arr) / sizeof ((arr)[0]))
> 
> I find the name of this macro to be unfortunate: what it returns is
> not "size" in the accepted meaning of that word.

"Length", "size", and "count" are hopelessly confounded anyway. I'm not
attached to any particular term: I chose EARRAYSIZE because ARRAYSIZE
and ARRAY_SIZE hace been common in other projects I've worked on.

> How about ALEN, or ARRAYELTS instead?

Of these, I prefer ARRAYELTS. I'll change the name.


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Re: EARRAYSIZE

[David Kastrup]

Daniel Colascione <dancol@dancol.org> writes:

> On 04/03/2014 12:30 PM, Eli Zaretskii wrote:
>>   +/* Find number of elements in array */
>>   +#define EARRAYSIZE(arr) (sizeof (arr) / sizeof ((arr)[0]))
>> 
>> I find the name of this macro to be unfortunate: what it returns is
>> not "size" in the accepted meaning of that word.
>
> "Length", "size", and "count" are hopelessly confounded anyway. I'm not
> attached to any particular term: I chose EARRAYSIZE because ARRAYSIZE
> and ARRAY_SIZE hace been common in other projects I've worked on.
>
>> How about ALEN, or ARRAYELTS instead?
>
> Of these, I prefer ARRAYELTS. I'll change the name.

Since Elisp has (length "333"), (length '(4 5 6)), and (length [4 5 3]),
for Emacs code LENGTH or LEN should be a reasonably straightforward
naming choice.

-- 
David Kastrup

Re: EARRAYSIZE

[Eli Zaretskii]

> From: David Kastrup <dak@gnu.org>
> Date: Thu, 03 Apr 2014 22:10:08 +0200
> 
> Daniel Colascione <dancol@dancol.org> writes:
> 
> > On 04/03/2014 12:30 PM, Eli Zaretskii wrote:
> >>   +/* Find number of elements in array */
> >>   +#define EARRAYSIZE(arr) (sizeof (arr) / sizeof ((arr)[0]))
> >> 
> >> I find the name of this macro to be unfortunate: what it returns is
> >> not "size" in the accepted meaning of that word.
> >
> > "Length", "size", and "count" are hopelessly confounded anyway. I'm not
> > attached to any particular term: I chose EARRAYSIZE because ARRAYSIZE
> > and ARRAY_SIZE hace been common in other projects I've worked on.
> >
> >> How about ALEN, or ARRAYELTS instead?
> >
> > Of these, I prefer ARRAYELTS. I'll change the name.
> 
> Since Elisp has (length "333"), (length '(4 5 6)), and (length [4 5 3]),
> for Emacs code LENGTH or LEN should be a reasonably straightforward
> naming choice.

I suggested ALEN because we have AREF and ASIZE.  Maybe AELTS or
ALENGTH would be better.

Re: EARRAYSIZE

[Paul Eggert]

Eli Zaretskii wrote:
> I suggested ALEN because we have AREF and ASIZE.  Maybe AELTS or
> ALENGTH would be better.

The most common name for this macro in other projects is probably 
ARRAY_SIZE.  That's what's in libiberty, for example.  There are other 
names (ARRAY_CARDINALITY, SIZEOF) but ARRAY_SIZE seems to be more popular.

Re: EARRAYSIZE

[Dmitry Antipov]

On 04/04/2014 11:45 AM, Eli Zaretskii wrote:

> I suggested ALEN because we have AREF and ASIZE.  Maybe AELTS or
> ALENGTH would be better.

IMO this will confuse the reader because AREF and ASIZE are for Lisp_Objects and not for C arrays.

What about MS-style countof (http://msdn.microsoft.com/en-us/library/ms175773%28v=VS.100%29.aspx)?

Dmitry

Re: EARRAYSIZE

[Eli Zaretskii]

> Date: Fri, 04 Apr 2014 01:04:37 -0700
> From: Paul Eggert <eggert@cs.ucla.edu>
> CC: emacs-devel@gnu.org
> 
> Eli Zaretskii wrote:
> > I suggested ALEN because we have AREF and ASIZE.  Maybe AELTS or
> > ALENGTH would be better.
> 
> The most common name for this macro in other projects is probably 
> ARRAY_SIZE.  That's what's in libiberty, for example.  There are other 
> names (ARRAY_CARDINALITY, SIZEOF) but ARRAY_SIZE seems to be more popular.

The SIZE part was what I originally objected: "size" in C is mostly
measured in bytes, which this one isn't.  ARRAY_SIZE will be confusing
since we already have ASIZE.

Re: EARRAYSIZE

[Eli Zaretskii]

> Date: Fri, 04 Apr 2014 12:06:59 +0400
> From: Dmitry Antipov <dmantipov@yandex.ru>
> CC: emacs-devel@gnu.org
> 
> On 04/04/2014 11:45 AM, Eli Zaretskii wrote:
> 
> > I suggested ALEN because we have AREF and ASIZE.  Maybe AELTS or
> > ALENGTH would be better.
> 
> IMO this will confuse the reader because AREF and ASIZE are for Lisp_Objects and not for C arrays.

It could, yes.

> What about MS-style countof (http://msdn.microsoft.com/en-us/library/ms175773%28v=VS.100%29.aspx)?

I'd prefer a capitalized name, FWIW.

Re: EARRAYSIZE

[David Kastrup]

Paul Eggert <eggert@cs.ucla.edu> writes:

> Eli Zaretskii wrote:
>> I suggested ALEN because we have AREF and ASIZE.  Maybe AELTS or
>> ALENGTH would be better.
>
> The most common name for this macro in other projects is probably
> ARRAY_SIZE.  That's what's in libiberty, for example.  There are other
> names (ARRAY_CARDINALITY, SIZEOF) but ARRAY_SIZE seems to be more
> popular.

I see it in the Git codebase.  I don't have the Linux source available
at the moment, but since it is involved with the same kind of crowd,
I consider it likely that they use it as well.

Even in Emacs, we have OBARRAY_SIZE defined as a member count rather
than a byte count (there is no other "ARRAY_SIZE" string in Emacs so
far).

Can't be that confusing to people.

-- 
David Kastrup