unofficial mirror of emacs-devel@gnu.org 
 help / color / mirror / code / Atom feed
From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Philipp Stephani <p.stephani2@gmail.com>
Cc: emacs-devel@gnu.org
Subject: Re: pure-fns in byte-opt.el
Date: Tue, 25 Jul 2017 17:27:31 -0400	[thread overview]
Message-ID: <jwvpocomcol.fsf-monnier+Inbox@gnu.org> (raw)
In-Reply-To: <CAArVCkQizDCZFB4DtN5DAmZMUj3QGSygVwfAGw2rkXNd6kqa6A@mail.gmail.com> (Philipp Stephani's message of "Tue, 25 Jul 2017 20:57:58 +0000")

> Why? Its return value clearly only depends on its argument, and it doesn't
> change any global state. It's the poster child of a pure function!

  (let ((s (make-string 5 ?a)))
    (list (string-to-char s)
          (progn
            (aset s 0 ?b)
            (string-to-char s))))

If string-to-char were a pure function, it would return the same value
in both calls (since the arguments are `eq').


        Stefan



  reply	other threads:[~2017-07-25 21:27 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-25  2:06 pure-fns in byte-opt.el Mark Oteiza
2017-07-25  8:14 ` Andreas Schwab
2017-07-25 14:16   ` Stefan Monnier
2017-07-25 20:57     ` Philipp Stephani
2017-07-25 21:27       ` Stefan Monnier [this message]
2017-07-25 22:28         ` Clément Pit-Claudel
2017-07-26  0:08           ` Stefan Monnier
2017-07-26  7:39             ` Clément Pit-Claudel
2017-07-26 12:58               ` Stefan Monnier
2017-07-28 17:45         ` Philipp Stephani
2017-07-28 17:49           ` Stefan Monnier
2017-07-28 17:52             ` Philipp Stephani
2017-07-28 22:20               ` Stefan Monnier
2017-09-24  7:31                 ` Philipp Stephani
2017-09-24 16:23                   ` Stefan Monnier
2017-09-25 22:06                     ` Richard Stallman
2017-09-26  0:25                       ` Stefan Monnier
2020-07-25 19:53                         ` Philipp Stephani
2020-07-25 19:58                           ` Stefan Monnier
2020-07-25 20:08                             ` Philipp Stephani
2020-07-25 20:59                               ` Stefan Monnier
2020-07-29 14:21                                 ` Philipp Stephani
2020-07-29 14:25                                   ` Stefan Monnier
2017-09-24 16:26                   ` Drew Adams
2017-07-26  1:00   ` Mark Oteiza
2017-07-26 14:33     ` Eli Zaretskii
2017-07-27  2:36       ` Mark Oteiza
2017-07-27  2:46         ` Stefan Monnier
2017-07-29 16:43           ` Mark Oteiza
2017-07-29 17:22             ` Eli Zaretskii
2017-07-29 19:48               ` Mark Oteiza
2017-07-29 20:03                 ` Andreas Schwab
2017-07-29 20:14                   ` Mark Oteiza
2017-07-27 17:06         ` Eli Zaretskii
2017-07-28  0:24           ` Mark Oteiza
2017-07-28  7:02             ` Eli Zaretskii
2017-07-29  1:24               ` Mark Oteiza
2017-07-29  7:24                 ` Eli Zaretskii
2017-07-29 16:34                   ` Mark Oteiza
2017-07-29 17:21                     ` Eli Zaretskii
2017-09-24  7:34                       ` Philipp Stephani
2017-09-24 16:24                         ` Stefan Monnier
2017-09-24 23:22                         ` John Wiegley

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: https://www.gnu.org/software/emacs/

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=jwvpocomcol.fsf-monnier+Inbox@gnu.org \
    --to=monnier@iro.umontreal.ca \
    --cc=emacs-devel@gnu.org \
    --cc=p.stephani2@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://git.savannah.gnu.org/cgit/emacs.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).