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From: Alan Mackenzie <acm@muc.de>
To: help-gnu-emacs@gnu.org
Subject: Re: Is it possible for a macro to expand to nothing?
Date: Fri, 27 Nov 2009 13:15:07 +0000 (UTC)	[thread overview]
Message-ID: <heojcr$1a4h$2@colin2.muc.de> (raw)
In-Reply-To: mailman.11626.1259310779.2239.help-gnu-emacs@gnu.org

Kevin Rodgers <kevin.d.rodgers@gmail.com> wrote:
> Alan Mackenzie wrote:

>> Your notion of the correct use of macros seems to be a religious idea
>> rather than one fully thought through.  You justify it with circular
>> reasoning.  Whilst using a macro to generate an evalable form may be
>> the most usual thing, there is no reason not to use it to produce
>> other list structure.

> Except that such macros can only be executed in a particular context
> i.e.  they depend on something that cannot be expressed via their
> argument list.

Yes, many lisp structures can only be "executed" in particular contexts,
`,@' for example, yet nobody slags them off for that.


> At best that is poor style, and at worst it is poor engineering.

That is so supercilious - you haven't even given an example of this
phenomenom, discussing why it is poor style or poor engineering.  There's
just this vague insinuation that you know better.

I will give an example, namely `c-lang-defconst' from cc-defs.el.  Are
you going to assert that it is poor style, or even poor engineering,
simply because it generates an internal data structure rather than an
excutable form?  If so, then it's up to you to say how it could have been
done better, preferably submitting a patch.

-- 
Alan Mackenzie (Nuremberg, Germany).



  parent reply	other threads:[~2009-11-27 13:15 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-23 14:56 Is it possible for a macro to expand to nothing? Alan Mackenzie
2009-11-23 16:03 ` Drew Adams
     [not found] ` <mailman.11344.1258992201.2239.help-gnu-emacs@gnu.org>
2009-11-23 16:31   ` Alan Mackenzie
2009-11-23 17:29     ` Drew Adams
2009-11-23 18:33     ` Pascal J. Bourguignon
2009-11-23 18:51       ` Drew Adams
     [not found]       ` <mailman.11354.1259004470.2239.help-gnu-emacs@gnu.org>
2009-11-23 20:08         ` Pascal J. Bourguignon
2009-11-23 20:24           ` Alan Mackenzie
2009-11-23 22:09           ` Drew Adams
     [not found]           ` <mailman.11367.1259014174.2239.help-gnu-emacs@gnu.org>
2009-11-23 23:55             ` Pascal J. Bourguignon
2009-11-24  0:55               ` Alan Mackenzie
2009-11-24  9:42                 ` Pascal J. Bourguignon
2009-11-24 10:45                   ` Alan Mackenzie
2009-11-24 11:14                     ` Pascal J. Bourguignon
2009-11-24 16:39                       ` Alan Mackenzie
2009-11-24 19:17                         ` Pascal J. Bourguignon
2009-11-25 14:13                         ` Jeff Clough
     [not found]                         ` <mailman.11467.1259158369.2239.help-gnu-emacs@gnu.org>
2009-11-26  6:53                           ` Alan Mackenzie
2009-11-26 11:11                             ` Pascal J. Bourguignon
2009-11-26 11:52                               ` Lennart Borgman
     [not found]                               ` <mailman.11564.1259236392.2239.help-gnu-emacs@gnu.org>
2009-11-26 12:16                                 ` Pascal J. Bourguignon
2009-11-26 12:43                                   ` Lennart Borgman
2009-11-27  8:32                         ` Kevin Rodgers
     [not found]                         ` <mailman.11626.1259310779.2239.help-gnu-emacs@gnu.org>
2009-11-27 13:15                           ` Alan Mackenzie [this message]
2009-11-27 13:52                             ` Pascal J. Bourguignon
2009-11-27 16:57                               ` Alan Mackenzie
2009-11-27 17:09                                 ` Pascal J. Bourguignon
2009-11-27 17:19                               ` Helmut Eller
2009-11-27 17:45                                 ` Pascal J. Bourguignon
2009-11-27 23:17                             ` Tim X
2009-11-28  0:06                               ` Pascal J. Bourguignon
2009-11-28  8:29                                 ` Alan Mackenzie
2009-11-28 10:25                                   ` Pascal J. Bourguignon
2009-11-28 12:57                                     ` Thierry Volpiatto
     [not found]                                     ` <mailman.11699.1259413441.2239.help-gnu-emacs@gnu.org>
2009-11-29  0:54                                       ` Pascal J. Bourguignon
2009-11-24 11:56                     ` Pascal J. Bourguignon
     [not found]     ` <mailman.11352.1258997403.2239.help-gnu-emacs@gnu.org>
2009-11-23 18:42       ` Pascal J. Bourguignon
2009-11-23 20:12         ` Drew Adams
     [not found]         ` <mailman.11356.1259007263.2239.help-gnu-emacs@gnu.org>
2009-11-23 20:21           ` Pascal J. Bourguignon
2009-11-23 22:09             ` Drew Adams
     [not found]             ` <mailman.11368.1259014177.2239.help-gnu-emacs@gnu.org>
2009-11-24  0:03               ` Pascal J. Bourguignon
2009-11-23 20:09       ` Alan Mackenzie
2009-11-23 16:49 ` Jeff Clough

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