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From: Andreas Schwab <schwab@linux-m68k.org>
To: Philip Kaludercic <philipk@posteo.net>
Cc: Lynn Winebarger <owinebar@gmail.com>,
	 Stefan Monnier <monnier@iro.umontreal.ca>,
	 Matthew Trzcinski <matt@excalamus.com>,
	emacs-devel <emacs-devel@gnu.org>
Subject: Re: [elpa] externals/org 26ef5e3e5b: org-src: Use `sh-mode' for all the shells it can handle
Date: Mon, 17 Apr 2023 18:37:51 +0200	[thread overview]
Message-ID: <875y9usbvk.fsf@igel.home> (raw)
In-Reply-To: <87bkjmh3st.fsf@posteo.net> (Philip Kaludercic's message of "Mon,  17 Apr 2023 16:27:46 +0000")

On Apr 17 2023, Philip Kaludercic wrote:

>> Why is the former more efficient than the latter?  It looks like the former
>> would have to construct the '(1 2) list twice, and the latter only once.
>> And the '(a b c d) cons cells are only allocated once either way.
>
> (I believe) It is more efficient, since there are fewer function calls.
> I have had issues in the past with ,@ expanding to code that would have
> exceeded the maximal evaluation depth, until I split it up and manually
> used `append' that has the advantage of being implemented in C.

cons is a bytecode intrinsic, so it shouldn't make that much of a
difference.
(cons 'a (cons 'b (cons 'c (cons 'd (list 1 2 3))))) is translated into

0	constant  a
1	constant  b
2	constant  c
3	constant  d
4	constant  1
5	constant  2
6	constant  3
7	listN	  7

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."



  reply	other threads:[~2023-04-17 16:37 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <168174708495.14139.12756054653439048176@vcs2.savannah.gnu.org>
     [not found] ` <20230417155805.3E200C1391A@vcs2.savannah.gnu.org>
2023-04-17 16:08   ` [elpa] externals/org 26ef5e3e5b: org-src: Use `sh-mode' for all the shells it can handle Stefan Monnier
2023-04-17 16:16     ` Lynn Winebarger
2023-04-17 16:27       ` Philip Kaludercic
2023-04-17 16:37         ` Andreas Schwab [this message]
2023-04-17 16:42           ` Philip Kaludercic
2023-04-17 16:39         ` Mattias Engdegård
2023-04-17 16:47           ` Mattias Engdegård
2023-04-17 17:37           ` Stefan Monnier
2023-04-17 18:33             ` Mattias Engdegård
2023-04-17 20:08               ` Stefan Monnier
2023-04-18  9:50                 ` Mattias Engdegård
2023-04-17 17:11       ` Stefan Monnier
2023-04-17 17:24         ` Lynn Winebarger

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