Re: [Boost-users] Asymmetrical predicates in STL algorithms

From: David Abrahams (dave_at_[hidden])
Date: 2006-02-16 02:14:44

"Max Motovilov" <max_at_[hidden]> writes:

> Now, this:
>
> struct less {
>   bool operator()( const Object&, const Key& ) const;
>   bool operator()( const Key&, const Object& ) const;
> };
>
> lower_bound( v.begin(), v.end(), Key(something), less() );
>
> should work everywhere, or so I think. Would be nice to be able to create
> such an adaptor for a pair of  functions (or a pair of bind or lambda
> expressions for that matter). I blogged a simple solution (for functions
> only) here
> http://swsw.motovilov.net/weblogs/swsw/archives/2006/02/asymmetrical_pr.html
> but am wondering if perhaps I missed a generic solution in one of the Boost
> libraries, or there's one coming in the new release?

Well, standard libraries are now required to make it legal:

http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#270

And you can get an implementation where it works at

http://www.boost-consulting.com/vault/index.php?&direction=0&order=&directory=Algorithms/binary_search

HTH,
-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com