From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Noam Postavsky <npostavs@gmail.com>
Cc: Aidan Kehoe <kehoea@parhasard.net>,
31792@debbugs.gnu.org, Alan Mackenzie <acm@muc.de>
Subject: bug#31792: 27.0.50; Regression in #'labels, recent versions
Date: Wed, 13 Jun 2018 23:32:02 -0400 [thread overview]
Message-ID: <jwvpo0udp27.fsf-monnier+emacsbugs@gnu.org> (raw)
In-Reply-To: <87muvyvym5.fsf@gmail.com> (Noam Postavsky's message of "Wed, 13 Jun 2018 23:24:50 -0400")
> (defmacro cl-flet (bindings &rest body)
> "Make local function definitions.
> -Like `cl-labels' but the definitions are not recursive.
> +Bind the function cells of symbols within FORM.
I think this is wrong: it makes it sound like it does `fset`, which
is what CL's `flet` did, but not what `cl-flet` does.
If you look at the implementation, you'll see that it doesn't touch any
"function cell".
> +The bindings only take effect within FORM, not BODY, so you can't
> +write recursive function definitions. Use `cl-labels' for that.
> +See info node `(cl) Function Bindings' for details.
This is good, thanks.
> (defmacro cl-labels (bindings &rest body)
> - "Make temporary function bindings.
> -The bindings can be recursive and the scoping is lexical, but capturing them
> -in closures will only work if `lexical-binding' is in use.
> + "Make local function definitions.
> +Bind the function cells of symbols within FORM.
Same here about "function cells".
> diff --git a/lisp/emacs-lisp/cl.el b/lisp/emacs-lisp/cl.el
> index d53c8e0bbc..f6643158d2 100644
> --- a/lisp/emacs-lisp/cl.el
> +++ b/lisp/emacs-lisp/cl.el
> @@ -466,9 +466,12 @@ labels
> (push var sets)
> (push (cons (car binding)
> `(lambda (&rest cl-labels-args)
> - (cl-list* 'funcall ',var
> - cl-labels-args)))
> + (if (eq (car cl-labels-args) cl--labels-magic)
> + (list cl--labels-magic ',var)
> + (cl-list* 'funcall ',var cl-labels-args))))
> newenv)))
> + ;; `lexical-let' adds `cl--function-convert' (which calls
> + ;; `cl--labels-convert') as a macroexpander for `function'.
> (macroexpand-all `(lexical-let ,vars (setq ,@sets) ,@body) newenv)))
Good, thanks.
Stefan
next prev parent reply other threads:[~2018-06-14 3:32 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-11 23:11 bug#31792: 27.0.50; Regression in #'labels, recent versions Aidan Kehoe
2018-06-11 23:31 ` Noam Postavsky
2018-06-12 22:58 ` Noam Postavsky
2018-06-13 13:16 ` Stefan Monnier
2018-06-14 3:24 ` Noam Postavsky
2018-06-14 3:32 ` Stefan Monnier [this message]
2018-06-14 4:13 ` Noam Postavsky
2018-06-14 18:05 ` Stefan Monnier
2018-06-20 0:08 ` Noam Postavsky
[not found] ` <mailman.1699.1528759928.1292.bug-gnu-emacs@gnu.org>
2018-06-13 16:57 ` Alan Mackenzie
2018-06-13 17:03 ` Noam Postavsky
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