From: Rivka Miller <rivkaumiller@gmail.com>
To: help-gnu-emacs@gnu.org
Subject: Re: `list-of' macro snippet [regarding Comprehensions]
Date: Sat, 3 Nov 2012 14:57:46 -0700 (PDT) [thread overview]
Message-ID: <556673a6-b350-49cc-905d-0662222ca071@g8g2000yqp.googlegroups.com> (raw)
In-Reply-To: 87pq3vmlg5.fsf@informatimago.com
On Nov 2, 8:09 pm, "Pascal J. Bourguignon" <p...@informatimago.com>
wrote:
> Rivka Miller <rivkaumil...@gmail.com> writes:
> > This is not that hard.
>
> > You can take the defmacro comp out of the defun.
>
> > It should not be hard
> > ----------------------------------------
> > background info in gnu.emacs.help
>
> > I spent a few hours poring over and fixed some of the variables and
> > backquotes and character codes.
>
> > The defmacro is now only nested in one function where it is needed.
> > Hope, someone can help get it to work and produce some kind of demo
> > examples.
>
> > (defun open-bracket (stream ch)
>
> > (defmacro comp ((e &rest qs) l2)
> > (if (null qs) `(cons ,e ,l2) ; rule A
> > (let ((q1 (car qs))
> > (q (cdr qs)))
> > (if (not(eq (cadr q1) '<-)) ; a generator?
> > `(if ,q1 (comp (,e ,@q),l2) ,l2) ; rule B
> > (let ((v (car q1)) ; rule C
> > (l1 (third q1))
> > (h (gentemp "H-"))
> > (us (gentemp "US-"))
> > (us1 (gentemp "US1-")))
> > `(labels ((,h (,us) ; corresponds to a letrec
> > (if (null ,us) ,l2
> > (let ((,v (car ,us))
> > (,us1 (cdr ,us)))
> > (comp (,e ,@q) (,h ,us1))))))
> > (,h ,l1)))))))
>
> > (do ((l nil)
> > (c (read stream t nil t)(read stream t nil t)))
> > ((eq c '|]|) `(comp ,(reverse l) ()))
> > (push c l))
> > )
>
> > (defun closing-bracket (stream ch) '|]|)
>
> > (eval-when (compile load eval)
> > (set-macro-character #\[ #'open-bracket)
> > (set-macro-character #\] #'closing-bracket))
>
> Why are you repeating this code here in comp.lang.lisp?
>
> I already told you that it was nonsensical!
>
> When you put the defmacro for inside the defun, it may not have
> compile-time effects. Therefore when you compile a file containing
> brackets, the reader macro function will be called, the macro will be
> defined, but maybe only into the run-time environment, not into the
> compilation environment. Therefore the compiler may not know that COMP
> is a macro, and it may very well signal an error when compiling a
> bracket expression!
>
> Why do you insist putting the defmacro inside the defun?
You must have read in a hurry. In previous post, I actually said
>> You can take the defmacro comp out of the defun.
Now, you can take it out and try to run it in emacs and put some run
examples.
R
next prev parent reply other threads:[~2012-11-03 21:57 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <44777946-db62-48fa-9e99-2fd06c6d296c@g18g2000vbf.googlegroups.com>
2012-10-29 0:49 ` `list-of' macro snippet [regarding Comprehensions] Rivka Miller
2012-10-29 2:20 ` Rivka Miller
2012-11-03 2:06 ` Rivka Miller
2012-11-03 3:09 ` Pascal J. Bourguignon
[not found] ` <87pq3vmlg5.fsf@informatimago.com>
2012-11-03 21:57 ` Rivka Miller [this message]
2012-11-07 17:08 ` Rivka Miller
2012-11-07 22:30 ` Pascal J. Bourguignon
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