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Re: [MIT-Scheme-devel] make-eq-hash-table
From: |
Joe Marshall |
Subject: |
Re: [MIT-Scheme-devel] make-eq-hash-table |
Date: |
Sun, 20 Dec 2009 07:55:07 -0800 |
On Sun, Dec 20, 2009 at 12:59 AM, Taylor R Campbell <address@hidden> wrote:
>
> The only reason that this may not have bitten anyone before is that
> nobody has implemented any weak internment scheme for objects that are
> ever used as keys in eq hash tables -- and the other cases are highly
> unlikely to be encountered.
I think this is the place where we disagree.
It seems to me that a weak internment scheme should not be observably
different from a strong one in any way. It should only be (potentially) more
memory efficient. This implies that if weakly interned objects are used
as keys in a hash table, then the entries they map to must be preserved
under all circumstances.
A weak-key EQ hash table should not be observably different from a strong
one with regard to the put and get operations. It may be observably different
in the count and key-list operations, that is, inaccessible entries would be
allowed to drop out. If the user doesn't want this, he should
use an EQUAL hash table.
--
~jrm
- [MIT-Scheme-devel] make-eq-hash-table, Taylor R Campbell, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Arthur A. Gleckler, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Joe Marshall, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Taylor R Campbell, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Joe Marshall, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Taylor R Campbell, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table,
Joe Marshall <=
- Re: [MIT-Scheme-devel] make-eq-hash-table, Taylor R Campbell, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Joe Marshall, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Taylor R Campbell, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Chris Hanson, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Arthur A. Gleckler, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Taylor R Campbell, 2009/12/20
- Re: [MIT-Scheme-devel] make-eq-hash-table, Chris Hanson, 2009/12/21
- Re: [MIT-Scheme-devel] make-eq-hash-table, Taylor R Campbell, 2009/12/21
- Re: [MIT-Scheme-devel] make-eq-hash-table, Chris Hanson, 2009/12/21
- Re: [MIT-Scheme-devel] make-eq-hash-table, Taylor R Campbell, 2009/12/21