Re: [MIT-Scheme-devel] make-eq-hash-table

[Joe Marshall]

On Sun, Dec 20, 2009 at 12:25 AM, Taylor R Campbell <address@hidden> wrote:
>   Date: Sun, 20 Dec 2009 00:07:17 -0800
>   From: Joe Marshall <address@hidden>
>
>   Ignoring the issue of weak symbols for the moment, there is no need
>   to have strong references to the keys *unless* someone is depending
>   upon walking the hash table to find them.  (and they shouldn't)
>
> I don't buy `they shouldn't' unless we're prepared to eliminate
> HASH-TABLE/KEY-LIST, HASH-TABLE/DATUM-LIST, HASH-TABLE/FOR-EACH, &c.,
> and then rewrite everything that uses them to use a different
> abstraction.

I don't think so.  If a hash table is a mapping from key to value, then the
key list need only contain those items that could conceivably be looked up.
It *doesn't* need to contain keys that cannot appear as arguments to
hash-table/get   (a subtle difference)


-- 
~jrm