Re: [boost] [intrusive] advanced lookup/insertion suggestion

Subject: Re: [boost] [intrusive] advanced lookup/insertion suggestion
From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2012-02-15 06:01:25

El 15/02/2012 0:27, Rei Thiessen escribió:
> // library
> template<typename ElementType, typename KeyType>
> struct element_key_info
> {};
>
> // different name to avoid overload confusion.
> // instantiation succeeds only when
> // element_key_info is properly specialized
> template<typename KeyType>
> iterator unordered_set::find_key( KeyType const&  k )
> {...}
> // user
> namespace intrusive{
> template<>
> struct element_key_info<element_type,key_type>
> {
> 	typedef key_hash hash_type;
> 	typedef key_equality equality_type;
> };
> }

Then for an element we have only one possible hash and comparison type, 
and that's not acceptable. A user might want to use a better hash 
function or just compare some set fields for equality but not all of them.

Ion