Re: [Boost-users] [Boost.Bind] and [Boost.Lambda] problem with partial application and curry

From: Kirit Sælensminde (kirit.saelensminde_at_[hidden])
Date: 2007-09-29 05:33:43

Peter Dimov wrote:
> Kirit Sælensminde:
> 
>> template< typename R, typename V1, typename V2 >
>> boost::function< boost::function< R ( V1 ) > ( V2 ) > curry(
>> boost::function< R ( V1, V2 ) > f ) {
>> return boost::bind( papply< R, V1, V2 >, f, _1 );
>> }
> 
> ...
> 
>> boost::function< boost::function< int ( int ) > ( boost::function< int
>> ( int, int ) >, int ) > fpapply( papply< int, int, int > );
> 
> ...
> 
>> //curry( fpapply );
> 
> Terrific.

As in inducing terror? :)

> 
> It seems that fpapply is of the form function<R(V1)>(V2,V3), and curry wants 
> function<R(V1)>(V2). 

The argument to curry is a binary function of this form:

boost::function<
        R (
                V1,
                V2 ) >

fpapply is of this type:

boost::function<
        boost::function< int ( int ) > ( // curry's R
                boost::function< int( int, int ) >, // curry's V1
                int ) > // curry's V2

papply itself is this:

        boost::function< R ( V2 ) > papply( // curry's R
                boost::function< R ( V1, V2 ) > f, // curry's V1
                V1 v ) // curry's V2

These are in the same form, it's just that V1 is now a function rather 
than a value. To me it looks like I should be able to pass this in as 
the binary function to curry.

K