From: "Linus Björnstam" <linus.bjornstam@veryfast.biz>
To: "Ludovic Courtès" <ludo@gnu.org>,
"Aleix Conchillo Flaqué" <aconchillo@gmail.com>
Cc: guile-user <guile-user@gnu.org>, guile-devel <guile-devel@gnu.org>
Subject: Re: Guile's time execution issues
Date: Mon, 04 May 2020 13:19:34 +0200 [thread overview]
Message-ID: <b28a393e-df0f-4ea9-a463-131c96b57f2d@www.fastmail.com> (raw)
In-Reply-To: <87r1w0rqhc.fsf@gnu.org>
On Mon, 4 May 2020, at 11:36, Ludovic Courtès wrote:
> > One thing I found is that `match` is slow. The code looked nicer but had to change it back to lets and conds as the performance
> > increase was ~2 seconds.
>
> Oh, in which case exactly? And are you sure your hand-written code is
> equivalent to the ‘match’ code (it’s common for hand-written code to be
> more lax than ‘match’)?
>
> One thing to pay attention to is the use of ‘list?’, which is O(N), and
> is implied by ellipses in ‘match’. If you want to use ‘match’ in a way
> that avoids ‘list?’, write patterns such as (a . b) instead of (a b ...).
> It doesn’t have the same meaning, but often the end result is the same,
> for instance because you’ll later match on ‘b’ anyway.
>
> (I wish we can one day have a proper list type disjoint from pairs…)
The change is here: he is only matching against chars and predicates: https://github.com/aconchillo/guile-json/commit/ad4b06d86e4822466983d00f55474c8f664b538d
next prev parent reply other threads:[~2020-05-04 11:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 22:03 Guile's time execution issues Aleix Conchillo Flaqué
2020-04-22 13:47 ` Linus Björnstam
2020-04-26 17:16 ` Ludovic Courtès
2020-04-26 23:14 ` Aleix Conchillo Flaqué
2020-05-02 14:11 ` Ludovic Courtès
2020-05-04 0:32 ` Aleix Conchillo Flaqué
2020-05-04 9:36 ` Ludovic Courtès
2020-05-04 11:19 ` Linus Björnstam [this message]
2020-05-04 20:09 ` Ludovic Courtès
2020-05-04 20:50 ` Linus Björnstam
2020-05-08 11:31 ` Linus Björnstam
2020-05-04 18:47 ` Linus Björnstam
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