From: David Kastrup <dak@gnu.org>
To: guile-devel@gnu.org
Subject: Growable arrays?
Date: Sat, 09 Jun 2012 14:32:28 +0200 [thread overview]
Message-ID: <87hauku0mb.fsf@fencepost.gnu.org> (raw)
Hi,
the main data structure of Lua is a "table", an associative array, and a
table t has a continguous numerically addressed part from 1..#t, with
all other indices going through a hashing mechanism. One principal
distinguishing feature, like with a Scheme hashtable, is the ability to
grow on-demand.
Scheme/Guile vectors are fixed size. Now I have a situation where I
have a basic type lattice with records stored in vectors, and this type
lattice may be extended dynamically (which typically happens at the
start of a whole file, for potentially multi-file runs). Scheme does
not offer a suitable data structure for that. It is a bit of a nuisance
that one can grow a hashtable efficiently and on-demand, but not so an
array.
Now it would be possible when the type lattice gets extended to store
the new entries in a hashtable and go from there. Or put them into a
list, and reallocate on first access beyond the existing element. That
seems rather contorted. And since there is, if I remember, a project to
run Lua on top of Guile, having a fundamental and reasonably efficient
data structure corresponding to a Lua table, or at least the contiguous
part of a Lua table, would seem like a reasonably useful idea. After
all, there already _is_ such a mechanism underlying hash tables so it
seems somewhat peculiar not to have it available for vectors as well.
Suggestions?
--
David Kastrup
next reply other threads:[~2012-06-09 12:32 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-09 12:32 David Kastrup [this message]
2012-06-09 14:43 ` Growable arrays? Krister Svanlund
2012-06-09 17:35 ` David Kastrup
2012-06-11 4:23 ` Daniel Hartwig
2012-06-11 4:37 ` David Kastrup
2012-06-11 5:00 ` Daniel Hartwig
2012-06-11 7:25 ` David Kastrup
2012-06-11 9:01 ` Daniel Hartwig
2012-06-11 9:13 ` Daniel Hartwig
2012-06-11 10:38 ` David Kastrup
2012-06-11 11:57 ` Daniel Hartwig
2012-06-11 12:13 ` Noah Lavine
2012-06-11 12:28 ` David Kastrup
2012-06-11 23:50 ` Mark H Weaver
2012-06-12 9:34 ` David Kastrup
2012-06-12 20:34 ` Mark H Weaver
2012-06-12 20:47 ` David Kastrup
2012-06-12 21:03 ` Mark H Weaver
2012-06-12 21:18 ` David Kastrup
2012-06-11 8:14 ` Thien-Thi Nguyen
2012-06-11 9:08 ` Andy Wingo
2012-06-11 9:55 ` David Kastrup
2012-06-11 11:25 ` Andy Wingo
2012-06-11 12:00 ` David Kastrup
2012-06-11 12:12 ` David Kastrup
2012-06-11 12:20 ` David Kastrup
2012-06-11 13:04 ` Daniel Hartwig
2012-06-11 14:19 ` David Kastrup
2012-06-11 15:24 ` Stefan Israelsson Tampe
2012-06-11 15:27 ` Andy Wingo
2012-06-11 16:03 ` David Kastrup
2012-06-11 12:20 ` Daniel Hartwig
2012-06-11 12:36 ` David Kastrup
2012-06-11 12:02 ` Ludovic Courtès
2012-06-12 13:36 ` Hans Aberg
2012-06-14 14:33 ` Mark H Weaver
2012-06-14 14:47 ` David Kastrup
2012-06-14 15:23 ` Daniel Hartwig
2012-06-14 15:34 ` David Kastrup
2012-06-14 16:56 ` Daniel Hartwig
2012-06-14 17:15 ` David Kastrup
2012-06-14 17:23 ` Daniel Hartwig
2012-06-14 17:49 ` David Kastrup
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