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From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Klaus-Dieter Bauer <bauer.klaus.dieter@gmail.com>
Cc: Sebastian Wiesner <lunaryorn@gmail.com>, emacs-devel@gnu.org
Subject: Re: Can the byte-compiler check whether functions passed by name are defined?
Date: Sun, 04 Aug 2013 17:11:51 -0400	[thread overview]
Message-ID: <jwvwqo12n1l.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <CANtbJLEBZUmtE8XnsiVaPKUx7jj1Cm_8vq7ddiZb7UNQw07S-w@mail.gmail.com> (Klaus-Dieter Bauer's message of "Sun, 4 Aug 2013 20:41:13 +0200")

>  I have written an implementation of the compile-time check, see the
> attached patch to "lisp/bytecomp.el". Since I also introduced as new
> declare form for `defun', I have also attached a patch to
> "doc/functions.texi".

That looks a lot more complex than what I expected.
As mentioned, the best option is to start by adding warnings for the
#'symbol form (should be easy: handle it in the same way we handle
warnings for function calls).

Then make the higher-order functions turn 'symbol into #'symbol.
That's important for things like

   (if foo #'a #'b)

> (defun my-combine (func1 func2)
>   (declare (higher-order-arguments 0 1)

Sadly, I defined the `compiler-macro' declaration to take a function
rather than an exp that returns a function, so you can't just
write a function macroexp--rewrite-function-arguments and then use:

  (defun my-combine (func1 func2)
    (declare (compiler-macro (macroexp--rewrite-function-arguments 0 1)))

But you can do something like
    
  (defun my-combine (func1 func2)
    (declare (compiler-macro
              (lambda (body)
                (macroexp--rewrite-function-arguments
                  body (rewrite func1) (rewrite func2)))))

  (defun my-mapcar (func list)
    (declare (compiler-macro
              (lambda (body)
                (macroexp--rewrite-function-arguments
                  body (rewrite func) list))))

Still, this annotation is only needed to turn a ' into a #', so it's not
the most important.
                  
> I couldn't define the handler in "byte-run.el" however, as when I added it
> to the declaration of `defun-declaration-alist', it would suddenly be
> missing again during compilation.

Probably because you didn't re-dump Emacs (byte-run.el is preloaded
into the `emacs' executable so if you change it, you need to rebuild
`emacs').


        Stefan



  reply	other threads:[~2013-08-04 21:11 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-29 10:35 Can the byte-compiler check whether functions passed by name are defined? Klaus-Dieter Bauer
2013-07-29 15:21 ` Stefan Monnier
2013-07-31 13:44   ` Klaus-Dieter Bauer
2013-07-31 17:49     ` Stefan Monnier
2013-07-31 18:01       ` Sebastian Wiesner
2013-08-01 20:31         ` Stefan Monnier
2013-08-04 18:41           ` Klaus-Dieter Bauer
2013-08-04 21:11             ` Stefan Monnier [this message]
2013-08-05  8:52               ` Klaus-Dieter Bauer
2013-08-05 14:35                 ` Stefan Monnier
2013-08-05 18:17                   ` Klaus-Dieter Bauer
2013-08-07 11:27                     ` Klaus-Dieter Bauer
2013-08-07 14:41                     ` Stefan Monnier
2013-08-07 15:11                       ` Klaus-Dieter Bauer
2013-08-07 15:21                         ` Stefan Monnier
2013-08-07 17:34                           ` Stefan Monnier
2013-08-07 21:11                             ` Glenn Morris
2013-08-07 21:59                               ` Glenn Morris
2013-08-08  1:25                                 ` Stefan Monnier
2013-08-08  8:44                                   ` Klaus-Dieter Bauer
2013-08-08 13:07                                     ` Stefan Monnier
2013-08-07 19:59                           ` Klaus-Dieter Bauer
2013-08-07 21:14                             ` Stefan Monnier

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