From: Barry Margolin <barmar@alum.mit.edu>
To: help-gnu-emacs@gnu.org
Subject: Re: plists, alists, and hashtables
Date: Wed, 05 Aug 2015 15:30:07 -0400 [thread overview]
Message-ID: <barmar-A2DC81.15300705082015@88-209-239-213.giganet.hu> (raw)
In-Reply-To: 87oailbn8t.fsf@lifelogs.com
In article <87oailbn8t.fsf@lifelogs.com>,
Ted Zlatanov <tzz@lifelogs.com> wrote:
> I think these details are easily optimized at the C level. Clearly an
> alist is better as the *backend* hashtable implementation for up to 10,
> possibly up to 100 entries (depending on caching, pipelining, hashing
> function, and other factors). But the frontend presentation is what I'm
> concerned about. I think a better reader syntax for hashtables would
> make them easier to write and read in code and would error out if they
> are malformed. That's an improvement over alists and plists I think.
IIRC, at one time Symbolics had an implementation of Common Lisp
hashtables that chose different internal representations depending on
various attributes of the table, like the current size and equivalence
function.
But I think they got rid of this because there were bugs that occurred
as a result of the table changing reps on the fly, and I guess they
discovered that it didn't really buy that much in performance. For
instance, the break-even point for alists is probably pretty low, and
hash tables tended to be used for large tables.
Of course, that was before languages like Perl, PHP, and Javascript
popularized the idea of using small hash tables to implement structures.
--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
next prev parent reply other threads:[~2015-08-05 19:30 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-31 21:42 How to iterate over properties in a plist? Marcin Borkowski
2015-07-31 22:18 ` Stefan Monnier
2015-07-31 22:29 ` Marcin Borkowski
2015-07-31 22:42 ` Dmitry Gutov
2015-08-01 13:34 ` Michael Heerdegen
[not found] ` <mailman.7705.1438381807.904.help-gnu-emacs@gnu.org>
2015-07-31 23:33 ` Pascal J. Bourguignon
2015-08-01 22:49 ` Stefan Monnier
[not found] ` <mailman.7750.1438469396.904.help-gnu-emacs@gnu.org>
2015-08-04 10:15 ` plists, alists, and hashtables (was: How to iterate over properties in a plist?) Ted Zlatanov
2015-08-04 10:29 ` Nicolas Petton
[not found] ` <mailman.7809.1438684158.904.help-gnu-emacs@gnu.org>
2015-08-04 11:23 ` plists, alists, and hashtables Ted Zlatanov
2015-08-05 4:36 ` plists, alists, and hashtables (was: How to iterate over properties in a plist?) Rusi
2015-08-05 6:12 ` plists, alists, and hashtables Pascal J. Bourguignon
2015-08-05 9:47 ` Ted Zlatanov
2015-08-05 12:20 ` Rusi
2015-08-06 19:16 ` Stefan Monnier
[not found] ` <mailman.7892.1438888819.904.help-gnu-emacs@gnu.org>
2015-08-07 16:33 ` Rusi
2015-08-05 17:24 ` Pascal J. Bourguignon
2015-08-05 18:31 ` Ted Zlatanov
2015-08-05 19:30 ` Barry Margolin [this message]
2015-08-05 19:40 ` Robert Thorpe
2015-08-05 21:11 ` Pascal J. Bourguignon
2015-08-06 15:17 ` Ted Zlatanov
2015-08-06 18:46 ` Pascal J. Bourguignon
2015-08-06 20:19 ` Drew Adams
2015-08-06 21:08 ` Ted Zlatanov
2015-08-07 0:23 ` Pascal J. Bourguignon
2015-08-06 19:35 ` Stefan Monnier
2015-08-05 13:48 ` Drew Adams
2015-08-06 19:12 ` Stefan Monnier
[not found] ` <mailman.7890.1438888393.904.help-gnu-emacs@gnu.org>
2015-08-06 20:00 ` Pascal J. Bourguignon
2015-08-06 20:57 ` Ted Zlatanov
2015-08-06 21:10 ` Drew Adams
[not found] ` <mailman.7902.1438895429.904.help-gnu-emacs@gnu.org>
2015-08-06 21:15 ` Ted Zlatanov
2015-08-06 21:31 ` Stefan Monnier
2015-08-07 1:53 ` Ted Zlatanov
2015-08-07 7:34 ` Pascal J. Bourguignon
2015-08-07 16:32 ` Stefan Monnier
[not found] ` <mailman.7941.1438965165.904.help-gnu-emacs@gnu.org>
2015-08-08 3:48 ` Pascal J. Bourguignon
2015-08-08 13:42 ` Stefan Monnier
2015-08-08 14:51 ` Rusi
2015-08-07 0:08 ` Pascal J. Bourguignon
2015-08-07 2:14 ` Ted Zlatanov
2015-08-07 7:53 ` Pascal J. Bourguignon
2015-08-07 11:21 ` Ted Zlatanov
2015-08-07 11:47 ` Pascal J. Bourguignon
2015-08-07 17:21 ` Ted Zlatanov
2015-08-07 19:21 ` Stefan Monnier
[not found] ` <mailman.7952.1438975314.904.help-gnu-emacs@gnu.org>
2015-08-08 3:52 ` Pascal J. Bourguignon
2015-08-07 16:35 ` Stefan Monnier
[not found] <mailman.7856.1438803631.904.help-gnu-emacs@gnu.org>
2015-08-05 20:08 ` Ted Zlatanov
2015-08-05 20:45 ` Stefan Monnier
2015-08-05 21:36 ` Drew Adams
2015-08-05 21:41 ` Pascal J. Bourguignon
[not found] ` <mailman.7860.1438807554.904.help-gnu-emacs@gnu.org>
2015-08-06 1:32 ` Ted Zlatanov
[not found] ` <mailman.7862.1438810623.904.help-gnu-emacs@gnu.org>
2015-08-06 1:36 ` Ted Zlatanov
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