From: Ehsanul Hoque <ehsanul_g3@...>
Date: 2009-09-11T09:10:15+09:00
Subject: RE: What’s the best general implementation of custom #hash	methods?

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You could check out some of these (in several languages including Ruby): ht=
tp://www.partow.net/programming/hashfunctions/#Download

> Date: Fri=2C 11 Sep 2009 00:56:14 +0900
> From: shot@hot.pl
> Subject: What=92s the best general implementation of custom #hash	methods=
?
> To: ruby-talk@ruby-lang.org
>=20
> Hello=2C ruby-talk.
>=20
> What=92s the best (fast=2C yet with relatively few cases when equal hashe=
s
> are generated for non-eql objects) way to implement a hash method?
>=20
> Is XOR-ing the hashes of an object=92s instance variables (assuming that
> two objects are eql if their ivars are eql) a good general approach?
>=20
> I=92m asking because I use this pattern in my code=2C and it seems quite
> fast=3B I needed to work around a bug in MRI=92s Set#hash and this soluti=
on=B9
> seems about as fast as the original MRI=92s Set#hash. I=92m just not sure
> whether it=92s hashy enough (so to speak) in that two un-eql objects
> hashed in this way produce different hashes often enough.
>=20
> =B9 http://github.com/Chastell/art-decomp/commit/b465660b9dcc8eada86f50bb=
cb8f951aa8145a19
>=20
> =97 Shot
> --=20
> Ill-informed qmail-bashing is better than
> no qmail-bashing at all.      [Don Marti]

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