* bug#6750: Byte compiler: spurious message "cl used at runtime"
@ 2010-07-28 18:15 Alan Mackenzie
2010-07-28 23:01 ` Stefan Monnier
0 siblings, 1 reply; 6+ messages in thread
From: Alan Mackenzie @ 2010-07-28 18:15 UTC (permalink / raw)
To: 6750
Hi, Emacs,
In this macro declaration:
(defmacro c-declare-lang-variables ()
`(progn
,@(mapcan (lambda (init)
`(,(if (elt init 2)
`(defvar ,(car init) nil ,(elt init 2))
`(defvar ,(car init) nil))
(make-variable-buffer-local ',(car init))))
(cdr c-lang-variable-inits))))
, (from cc-engine.el), the byte-compiler gives this warning:
"Function `mapcan' from cl package called at runtime".
It is clear that the mapcan, being within a ,@ construct, does its work
at macro-expansion time, i.e. compile time.
Thus the warning message is wrong. This is a bug.
--
Alan Mackenzie (Nuremberg, Germany).
^ permalink raw reply [flat|nested] 6+ messages in thread* bug#6750: Byte compiler: spurious message "cl used at runtime"
2010-07-28 18:15 bug#6750: Byte compiler: spurious message "cl used at runtime" Alan Mackenzie
@ 2010-07-28 23:01 ` Stefan Monnier
2010-07-29 19:03 ` Alan Mackenzie
0 siblings, 1 reply; 6+ messages in thread
From: Stefan Monnier @ 2010-07-28 23:01 UTC (permalink / raw)
To: Alan Mackenzie; +Cc: 6750
> In this macro declaration:
> (defmacro c-declare-lang-variables ()
> `(progn
> ,@(mapcan (lambda (init)
> `(,(if (elt init 2)
> `(defvar ,(car init) nil ,(elt init 2))
> `(defvar ,(car init) nil))
> (make-variable-buffer-local ',(car init))))
> (cdr c-lang-variable-inits))))
> , (from cc-engine.el), the byte-compiler gives this warning:
> "Function `mapcan' from cl package called at runtime".
> It is clear that the mapcan, being within a ,@ construct, does its work
> at macro-expansion time, i.e. compile time.
> Thus the warning message is wrong. This is a bug.
This macro will be in the .elc. This means it can be called "at run
time" (e.g. if you do M-: (c-declare-lang-variables ...) RET).
Stefan
^ permalink raw reply [flat|nested] 6+ messages in thread* bug#6750: Byte compiler: spurious message "cl used at runtime"
2010-07-28 23:01 ` Stefan Monnier
@ 2010-07-29 19:03 ` Alan Mackenzie
2010-07-29 19:51 ` Juanma Barranquero
2010-07-30 9:18 ` Stefan Monnier
0 siblings, 2 replies; 6+ messages in thread
From: Alan Mackenzie @ 2010-07-29 19:03 UTC (permalink / raw)
To: Stefan Monnier; +Cc: 6750
Hi, Stefan,
On Thu, Jul 29, 2010 at 01:01:46AM +0200, Stefan Monnier wrote:
> > In this macro declaration:
> > (defmacro c-declare-lang-variables ()
> > `(progn
> > ,@(mapcan (lambda (init)
> > `(,(if (elt init 2)
> > `(defvar ,(car init) nil ,(elt init 2))
> > `(defvar ,(car init) nil))
> > (make-variable-buffer-local ',(car init))))
> > (cdr c-lang-variable-inits))))
> > , (from cc-engine.el), the byte-compiler gives this warning:
> > "Function `mapcan' from cl package called at runtime".
> > It is clear that the mapcan, being within a ,@ construct, does its work
> > at macro-expansion time, i.e. compile time.
> > Thus the warning message is wrong. This is a bug.
> This macro will be in the .elc. This means it can be called "at run
> time" (e.g. if you do M-: (c-declare-lang-variables ...) RET).
That brought a smile to my face. It's pure sophistry. :-) With no more
creativity than you've just shown, ANY use of mapcan could be "shown" to
be "use at runtime". So why not shorten the warning message to
"Function `mapcan' from cl package was used"
? ;-)
Or, perhaps you could indulge me a little, and show an example of mapcan
(or some other cl function) which isn't "use at runtime". You know as
well as I do, that there's no rigid separation of Lisp into compilation
and running phases.
I put it to you that that error message is not, in general, helpful. I
think it should be restricted to uses of mapcan at runtime (in a defun)
or when it's in the form generated by a macro.
I'm trying to get rid of warnings messages in CC Mode.
> Stefan
--
Alan Mackenzie (Nuremberg, Germany).
^ permalink raw reply [flat|nested] 6+ messages in thread* bug#6750: Byte compiler: spurious message "cl used at runtime"
2010-07-29 19:03 ` Alan Mackenzie
@ 2010-07-29 19:51 ` Juanma Barranquero
2010-07-30 9:18 ` Stefan Monnier
1 sibling, 0 replies; 6+ messages in thread
From: Juanma Barranquero @ 2010-07-29 19:51 UTC (permalink / raw)
To: Alan Mackenzie; +Cc: 6750
On Thu, Jul 29, 2010 at 21:03, Alan Mackenzie <acm@muc.de> wrote:
> Or, perhaps you could indulge me a little, and show an example of mapcan
> (or some other cl function) which isn't "use at runtime".
;; at top level
(eval-when-compile
(mapcan ...))
> I put it to you that that error message is not, in general, helpful. I
> think it should be restricted to uses of mapcan at runtime (in a defun)
> or when it's in the form generated by a macro.
But the point is that the macro could be called at runtime and
`mapcan' would not be defined.
Try byte-compiling test.el:
--------------------------------------------------------------------------------
(eval-when-compile (require 'cl))
(defmacro mapcan-at-runtime ()
`(setq sample ',(mapcan 'identity '((a) (b) (c)))))
--------------------------------------------------------------------------------
(which produces the warning), and then
emacs -Q -l test.elc
M-: (mapcan-at-runtime) <RET>
Juanma
^ permalink raw reply [flat|nested] 6+ messages in thread
* bug#6750: Byte compiler: spurious message "cl used at runtime"
2010-07-29 19:03 ` Alan Mackenzie
2010-07-29 19:51 ` Juanma Barranquero
@ 2010-07-30 9:18 ` Stefan Monnier
2011-07-14 13:28 ` Lars Magne Ingebrigtsen
1 sibling, 1 reply; 6+ messages in thread
From: Stefan Monnier @ 2010-07-30 9:18 UTC (permalink / raw)
To: Alan Mackenzie; +Cc: 6750
>> This macro will be in the .elc. This means it can be called "at run
>> time" (e.g. if you do M-: (c-declare-lang-variables ...) RET).
> That brought a smile to my face. It's pure sophistry. :-)
Except that this is not the reason I put the warning, but the reason why
the byte-compiler's code thinks the warning is warranted.
The byte-compiler is fairly stupid and doesn't know that this macro is
not intended to be used at runtime.
I agree it's not great, and it leads to "spurious" warnings like that.
Suggestions (and patches even better) welcome to try and resolve
the problem.
Stefan
^ permalink raw reply [flat|nested] 6+ messages in thread* bug#6750: Byte compiler: spurious message "cl used at runtime"
2010-07-30 9:18 ` Stefan Monnier
@ 2011-07-14 13:28 ` Lars Magne Ingebrigtsen
0 siblings, 0 replies; 6+ messages in thread
From: Lars Magne Ingebrigtsen @ 2011-07-14 13:28 UTC (permalink / raw)
To: Stefan Monnier; +Cc: 6750, Alan Mackenzie
Stefan Monnier <monnier@iro.umontreal.ca> writes:
> The byte-compiler is fairly stupid and doesn't know that this macro is
> not intended to be used at runtime.
The macro, however, is in the .elc file, so I don't think this is a
bug. (Although the warning could be changed to, perhaps, "cl in the
.elc file" or something.)
Anyway, I'm closing the report.
--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog http://lars.ingebrigtsen.no/
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-07-14 13:28 UTC | newest]
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2010-07-28 18:15 bug#6750: Byte compiler: spurious message "cl used at runtime" Alan Mackenzie
2010-07-28 23:01 ` Stefan Monnier
2010-07-29 19:03 ` Alan Mackenzie
2010-07-29 19:51 ` Juanma Barranquero
2010-07-30 9:18 ` Stefan Monnier
2011-07-14 13:28 ` Lars Magne Ingebrigtsen
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