all messages for Emacs-related lists mirrored at yhetil.org
 help / color / mirror / code / Atom feed
From: Stefan Monnier via "Emacs development discussions." <emacs-devel@gnu.org>
To: emacs-devel@gnu.org
Subject: Re: [GNU ELPA] New package: tam
Date: Wed, 20 Sep 2023 13:30:34 -0400	[thread overview]
Message-ID: <jwvh6noahtn.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: CAM=F=bA-uF2_KQyYC4FMwo3PfBtNJvyHLWguE6tJTzNTtm=uvw@mail.gmail.com

>> Re your last change in [0], why use records directly instead of having
>> the code being generated via cl-defstruct?  The commit messages doesn't
>> really explain your reasoning to me.
> The library is supposed to provide alloc/free functions that run in
> O(1) time to the extent that is possible for emacs-lisp code, for use
> in process sentinels and similar situations.  I took a look at the
> byte-code generated for those two functions when using the
> cl-defstruct definitions, and the accessors and setters were
> not inlined.

That's odd.  Could you give more details about what&how you checked that?

> Aside from the unknown complexity of invoking those functions, every
> call has a risk of overflowing the current stack and requiring an
> additional stack segment be allocated.

That would still be O(1) in my book.

> Accumulating a list in the right order is only O(n^2) if you only keep
> the head of the list.  The queue structure (or what I would write with
> let-bound variables) holds a reference to the last cons cell of the
> list to use in adding an entry on the end.  It's probably negligible
> for very short lists, but it's just bad form.

Using `push`es followed by `nreverse` is usually more efficient than
either of those.  It's a standard idiom in Lisp for good reasons.
If you care about the constant of your O(1) above, I recommend you use
`nreverse` here as well :-)


        Stefan




  reply	other threads:[~2023-09-20 17:30 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-18  2:28 [GNU ELPA] New package: tam Lynn Winebarger
2023-09-18  9:37 ` Philip Kaludercic
2023-09-18 16:22   ` Lynn Winebarger
2023-09-18 17:02     ` Philip Kaludercic
2023-09-19 15:38       ` Lynn Winebarger
2023-09-20  8:26         ` Philip Kaludercic
2023-09-20 16:14           ` Lynn Winebarger
2023-09-20 17:30             ` Stefan Monnier via Emacs development discussions. [this message]
2023-09-21  4:21               ` Lynn Winebarger
2023-09-21 13:59                 ` Stefan Monnier
2023-09-22  3:01                   ` Lynn Winebarger
2023-09-22  3:23                     ` Stefan Monnier
2023-09-21 16:38             ` Philip Kaludercic
2023-09-18 19:26 ` Adam Porter
2023-09-19 15:48   ` Lynn Winebarger
2023-09-19 16:29     ` Adam Porter
2023-09-21 20:26     ` Richard Stallman
2023-09-22 19:45       ` Adam Porter
2023-09-20 16:06 ` Stefan Monnier
2023-09-20 16:44   ` Lynn Winebarger

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

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

  git send-email \
    --in-reply-to=jwvh6noahtn.fsf-monnier+emacs@gnu.org \
    --to=emacs-devel@gnu.org \
    --cc=monnier@iro.umontreal.ca \
    /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 external index

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

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.