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From: Michael Heerdegen <michael_heerdegen@web.de>
To: npostavs@users.sourceforge.net
Cc: 27016@debbugs.gnu.org,
	Rafael D Sorkin <rsorkin@perimeterinstitute.ca>,
	Stefan Monnier <monnier@iro.umontreal.ca>
Subject: bug#27016: possible bug in `defsetf'
Date: Fri, 26 May 2017 01:40:16 +0200	[thread overview]
Message-ID: <87d1awmrof.fsf@drachen> (raw)
In-Reply-To: <87mva05ykw.fsf@users.sourceforge.net> (npostavs's message of "Thu, 25 May 2017 19:03:11 -0400")

Hello,

I wonder now if the definition of `eval-and-compile' as defmacro is
correct.  Maybe Stefan can help (I CC'd him), he may also want to look
at the rest of the report...

npostavs@users.sourceforge.net writes:

> > #+begin_src emacs-lisp
> > (macroexpand '(defsetf foo bar))
> > ==>
> > '(lambda
> >    (do &rest args)
> >    (gv--defsetter 'foo
> >                   (lambda
> >                     (val &rest args)
> >                     `(,'bar ,@args ,val))
> >                   do args))
> > #+end_src
>
> I don't understand where that quote comes from.

The `defsetf' expands to an `eval-and-compile'.  The `eval-and-compile'
expands to a quoted constant, see its definition (as defmacro).


> > When you compile a file with this content:
> >
> > #+begin_src emacs-lisp
> > (eval-and-compile
> >   (unless nil
> >     (defsetf foo bar)))
> > #+end_src
> >
> > you get an empty .elc.
> >
> > Isn't that strange?
>
> Yeah, even stranger...

AFAIU, when compiled, `eval-and-compile' macroexpands its body (see the
defconst of `byte-compile-initial-macro-environment').  So what is
compiled is essentially

#+begin_src emacs-lisp
(if nil nil
  '(closure
    (t)
    (do &rest args)
    (gv--defsetter 'foo
                   (lambda
                     (val &rest args)
                     `(,'bar ,@args ,val))
                   do args)))
#+end_src

and that's just discarded.


Michael.





  reply	other threads:[~2017-05-25 23:40 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-22  6:39 bug#27016: possible bug in `defsetf' Rafael D Sorkin
2017-05-22 12:11 ` npostavs
2017-05-22 20:25 ` Rafael D Sorkin
2017-05-22 21:18   ` npostavs
2017-05-22 23:10     ` Michael Heerdegen
2017-05-22 23:23       ` npostavs
2017-05-23  0:45         ` Michael Heerdegen
2017-05-23  0:51           ` npostavs
2017-05-23  1:18             ` Michael Heerdegen
2017-05-22 22:03 ` Rafael D Sorkin
2017-05-22 23:15   ` npostavs
2017-05-24  4:52 ` Rafael D Sorkin
2017-05-24 22:51   ` Michael Heerdegen
2017-05-25  1:50     ` npostavs
2017-05-25  4:59 ` Rafael D Sorkin
2017-05-25  5:01 ` Rafael D Sorkin
2017-05-25 10:38   ` npostavs
2017-05-25 20:26     ` Michael Heerdegen
2017-05-25 20:42       ` Noam Postavsky
2017-05-25 21:31         ` Michael Heerdegen
2017-05-25 23:03           ` npostavs
2017-05-25 23:40             ` Michael Heerdegen [this message]
2017-05-26  3:50 ` Stefan Monnier
2017-05-26 22:51   ` npostavs
2017-05-28 20:45     ` Stefan Monnier
2017-07-02 20:47       ` npostavs
2017-07-03 11:25         ` Michael Heerdegen
2017-07-09 20:13           ` npostavs
2017-07-10  0:26             ` Michael Heerdegen
2017-07-11  1:45               ` npostavs
2017-07-11 16:21             ` Stefan Monnier
2017-07-12  0:55               ` npostavs
2017-07-12  2:01                 ` Stefan Monnier
2017-07-13  4:46                   ` npostavs
2017-07-13 14:25                     ` Stefan Monnier
2017-07-14  0:39                       ` npostavs
2017-07-14  3:48                         ` Stefan Monnier
2017-07-14  4:32                           ` Stefan Monnier
2017-07-15 14:51                             ` npostavs
2017-07-16  1:03                               ` Stefan Monnier
2017-08-08  1:18                                 ` npostavs
2017-05-26  5:05 ` Rafael D Sorkin

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