Subject: Re: what happened to hash-tables
From: (Rob Warnock)
Date: Mon, 20 Sep 2004 20:02:33 -0500
Newsgroups: comp.lang.lisp
Message-ID: <>
Pascal Bourguignon  <> wrote:
| Duane Rettig <> writes:
| > But of course each implementation is free to extend the interface,
| > and the result can be precisely this freedom to specify any test
| > function and/or hash generator:
| >
| It's not good enough.  People have been burned before with proprietary
| extensions (when the vendor disappears or change his specifications
| without notice).  We won't be using vendor specific extensions anymore
| in this life!

Well, that's a rather absolutist posture. The Franz hash/test
function extension is quite similar to the CMUCL (and probably
SBCL too, though I haven't looked) DEFINE-HASH-TABLE-TEST extension
(which likewise also defines a hash function to pair with the test),
and the syntactic differences could easily be papered over with
feature tests. So if you *need* it, why not use it?


p.s. The Franz extension for weak keys/values looks like a
reasonable & useful one for people to copy in other implementations
as well...

Rob Warnock			<>
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