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From: Michael Heerdegen <michael_heerdegen@web.de>
To: help-gnu-emacs@gnu.org
Subject: Re: cl-loop - do you understand it well?
Date: Sun, 18 Dec 2022 01:16:30 +0100	[thread overview]
Message-ID: <874jtt36sh.fsf@web.de> (raw)
In-Reply-To: 871qoyoq0u.fsf@dataswamp.org

Emanuel Berg <incal@dataswamp.org> writes:

> >> Jokes that I don't understand aside, why does this return 4?
> >>
> >> (require 'cl-lib)
> >>
> >> (cl-loop
> >>   for i from 0 to 1
> >>   collect (lambda () i) into funs
> >>   finally return (apply #'+ (mapcar #'funcall funs)) )
> >
> > Because of internal implementation details?
>
> I don't think so, rather it has something to do with how
> `cl-loop' is programmed.

This was a joke, right?

Anyway,

#+begin_src emacs-lisp
(macroexpand-1
 '(cl-loop
   for i from 0 to 1
   collect (lambda () i) into funs
   finally return (apply #'+ (mapcar #'funcall funs))))
  ==>
  (cl-block nil
    (let* ((i 0)
           (funs nil))
      (while (<= i 1)
        (setq funs (nconc funs (list (lambda nil i))))
        (setq i (+ i 1)))
      (apply #'+ (mapcar #'funcall funs))))
#+end_src

Nearly the same code as we had discussed.  But I guess this was all
clear to you (or not?).

Michael.




  reply	other threads:[~2022-12-18  0:16 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-10  2:22 cl-loop - do you understand it well? Emanuel Berg
2022-12-10 18:56 ` Michael Heerdegen
2022-12-10 19:00   ` Akib Azmain Turja
2022-12-10 19:35     ` tomas
2022-12-10 20:48       ` Michael Heerdegen
2022-12-11  5:57         ` Akib Azmain Turja
2022-12-11 14:43           ` Stefan Monnier via Users list for the GNU Emacs text editor
2022-12-12  6:03             ` Akib Azmain Turja
2022-12-12  1:41           ` Michael Heerdegen
2022-12-14 23:53             ` Emanuel Berg
2022-12-16  0:25               ` Stefan Monnier via Users list for the GNU Emacs text editor
2022-12-17  0:02                 ` Emanuel Berg
2022-12-16  2:25               ` Michael Heerdegen
2022-12-17  0:03                 ` Emanuel Berg
2022-12-18  0:16                   ` Michael Heerdegen [this message]
2022-12-19 20:36                     ` Emanuel Berg
2022-12-21  8:12                       ` Michael Heerdegen

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