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Hash clash in polymorphic variants
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Date: -- (:)
From: Stefan Monnier <monnier@i...>
Subject: Re: Hash clash in polymorphic variants
>> > What I meant was simply that instead of using some fixed hash function,
>> > one could use a perfect hashing function which is optimal for its known
>> > set of inputs, and won't ever generate a collision.
>> 
>> The problem is that the set of inputs is not know at compile time, only
>> at link time.

> As I've said in the cited post, the perfect hash generator would have to be 
> invoked at link time, which shouldn't be a big deal.

That would require postponing the execution of the hash-function to
link-time or run-time.  Run-time is clearly undesirable, and link-time
adds yet-more complexity to the linker.

It's not a bad idea, obviously, but AFAICT the linker currently is kept
very simple.


        Stefan