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* Why a defmacro that calls a defun?
@ 2017-10-02 23:26 Eric Abrahamsen
  0 siblings, 0 replies; 3+ messages in thread
From: Eric Abrahamsen @ 2017-10-02 23:26 UTC (permalink / raw)
  To: help-gnu-emacs

I'm poking through Gnus, and seeing a fair number of places with code
that looks like this:

(defmacro nnoo-define-skeleton (backend)
  `(eval-and-compile
     (nnoo-define-skeleton-1 ',backend)))

(defun nnoo-define-skeleton-1 (backend)
  ...)

What does this actually do? All I can see happening is that a quote mark
is added before the BACKEND argument in the macro. What is happening
here?

Thanks,
Eric




^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Why a defmacro that calls a defun?
       [not found] <mailman.668.1506986797.27995.help-gnu-emacs@gnu.org>
@ 2017-10-03 17:24 ` Barry Margolin
  2017-10-03 18:20   ` Eric Abrahamsen
  0 siblings, 1 reply; 3+ messages in thread
From: Barry Margolin @ 2017-10-03 17:24 UTC (permalink / raw)
  To: help-gnu-emacs

In article <mailman.668.1506986797.27995.help-gnu-emacs@gnu.org>,
 Eric Abrahamsen <eric@ericabrahamsen.net> wrote:

> I'm poking through Gnus, and seeing a fair number of places with code
> that looks like this:
> 
> (defmacro nnoo-define-skeleton (backend)
>   `(eval-and-compile
>      (nnoo-define-skeleton-1 ',backend)))
> 
> (defun nnoo-define-skeleton-1 (backend)
>   ...)
> 
> What does this actually do? All I can see happening is that a quote mark
> is added before the BACKEND argument in the macro. What is happening
> here?

It just causes the function to be called at compile time as well as run 
time, due to the use of eval-and-compile.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Why a defmacro that calls a defun?
  2017-10-03 17:24 ` Why a defmacro that calls a defun? Barry Margolin
@ 2017-10-03 18:20   ` Eric Abrahamsen
  0 siblings, 0 replies; 3+ messages in thread
From: Eric Abrahamsen @ 2017-10-03 18:20 UTC (permalink / raw)
  To: help-gnu-emacs

Barry Margolin <barmar@alum.mit.edu> writes:

> In article <mailman.668.1506986797.27995.help-gnu-emacs@gnu.org>,
>  Eric Abrahamsen <eric@ericabrahamsen.net> wrote:
>
>> I'm poking through Gnus, and seeing a fair number of places with code
>> that looks like this:
>> 
>> (defmacro nnoo-define-skeleton (backend)
>>   `(eval-and-compile
>>      (nnoo-define-skeleton-1 ',backend)))
>> 
>> (defun nnoo-define-skeleton-1 (backend)
>>   ...)
>> 
>> What does this actually do? All I can see happening is that a quote mark
>> is added before the BACKEND argument in the macro. What is happening
>> here?
>
> It just causes the function to be called at compile time as well as run 
> time, due to the use of eval-and-compile.

Huh, thanks for that. I guess it's obvious, but it was not clicking for me.




^ permalink raw reply	[flat|nested] 3+ messages in thread

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2017-10-03 17:24 ` Why a defmacro that calls a defun? Barry Margolin
2017-10-03 18:20   ` Eric Abrahamsen
2017-10-02 23:26 Eric Abrahamsen

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