GNU bug report logs -
#65344
28.2; Unable to Edebug cl-flet form which uses argument destructuring
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Reported by: Brandon Irizarry <brandon.irizarry <at> gmail.com>
Date: Wed, 16 Aug 2023 18:23:02 UTC
Severity: normal
Found in version 28.2
Fixed in version 30.1
Done: Gerd Möllmann <gerd.moellmann <at> gmail.com>
Bug is archived. No further changes may be made.
Full log
Message #35 received at 65344 <at> debbugs.gnu.org (full text, mbox):
[Message part 1 (text/plain, inline)]
On 18.08.23 08:43, Gerd Möllmann wrote:
> On 18.08.23 07:58, Michael Heerdegen wrote:
>> Gerd Möllmann <gerd.moellmann <at> gmail.com> writes:
>>
>>> which I would naively expect to be suitable for a single function in
>>> an flet/labels. (Maybe without the (setf ...) case, I'm not sure
>>> ATM).
>>
>> That's correct, but only one part.
>
> RIght, that's what I meant.
>
>>> Do you perhaps have an insight why there are two &name in the flet
>>> spec?
>>
>> Eh - not really. That's some internal magic - to correctly associate
>> the code with the function names or something like that, I guess.
>
> Ok. It's probably not important.
>
>>> Also naively asked, what does the &or in the flet case mean? Does it
>>> say that that the elements of the flet can either be symbols or
>>> functions?
>>
>> There is a second syntax to support: a function binding can also have
>> the syntax (fname EXPR) instead of (fname args body...). EXPR can be a
>> lambda expression but also any arbitrary Lisp returning a function
>> value.
>
> (Another nominee for the most obscure feature of the month. That's also
> not in CL, BTW.)
>
> When I try something like
>
> (cl-flet (y (x (lambda () 1)))
> (x))
>
> I get a not-a-list error from the Y. That's kind of what I'm wondering.
> The debug declaratino for flet has the symbolp at the same level as
> the local-function &define.
>
> And, if that's the problem, the next question would then be how to
> declare a binding (FN VALUE). Maybe (%define &name ... <something>)?
The Elisp manual has very nice description of debug specs, indeed.
It's under Elisp > Edebug > Edebug and Macros > Specification Lists.
From that description, I think this is the right debug spec for flet
(patch attached)
(debug ((&rest [&or (&define [&name symbolp "@cl-flet@"]
[&name [] gensym] ;Make it unique!
cl-lambda-list
cl-declarations-or-string
[&optional ("interactive" interactive)]
def-body)
(&define [&name symbolp "@cl-flet@"]
[&name [] gensym] ;Make it unique!
def-body)])
The second &define is for the (FN EXPR) bindings. It comes after the
&define for "normal" function bindings because because, for some reason,
apparently the second &define also matches the other case. (The
description in the Elisp manual, BTW, also explain what the duplicate
name does, although I'm not sure why it is done here, because the names
of the local functions should be unique already. I'm probably
overlooking something.)
Seems to work for me. WDYT?
[flet.patch (text/plain, attachment)]
This bug report was last modified 1 year and 261 days ago.
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