Re: hash tables without GC cost

[Sam S. <sd...@gn...>]

> * Bruno Haible <oe...@py...t> [2004-04-27 14:31:54 +0200]:
>
> Sam wrote:
>> Some smart-ass will use it in his HT and will be stunned with
>>
>>      (setf (gethash 'foo ht) 'bar)
>>      (gc)
>>      (gethash 'foo ht) ==> NIL
>>
>> are we willing to live with this?
>
> No, we can give an error during (setf gethash).

Alternatively, just mark the table as requiring a rehash.
Actually, just create all HTs as GC-INVARIANT and turn them into
non-invariant as needed.

>> if not, we can add a setfable SYS::HT-GC-INVARIANT-P.
>
> We can verify for the simple cases (EQ, EQL and CLASS-HASHCODE) that all
> keys in the hash table are GC-invariant.

yes, before marking the HT as GC-INVARIANT, a check should be required.

BTW, how about the tree hash code?
I sent you my patch a couple of times...

-- 
Sam Steingold (http://www.podval.org/~sds) running w2k
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