[julia-users] Re: Differences between == and indexing/keys?

[Steven G. Johnson]

On Tuesday, October 21, 2014 2:35:01 AM UTC-4, Joshua Job wrote:
>
> So would something like
> hash(x::ProblemInstance,h::Uint64=uint(0)) = 3*hash(x.h)+2*hash(x.J)+hash(
> x.properties)+h
> be a reasonable thing to do?
>

No, it is enough to define:

import Base: hash
hash(x::ProblemInstance, h::Uint64) = hash(x.h, hash(x.J, 
hash(x.properties, h)))


That is, you should use the hash(x,y) function itself to combine multiple 
hashes, not addition or any other ad-hoc bitmixing strategy.