Re: [Boost-users] [boost::function_types] Create function type from member function type

From: Peter Soetens (peter.soetens_at_[hidden])
Date: 2006-08-21 10:23:06

On Friday 18 August 2006 08:34, Tobias Schwinger wrote:
> Peter Soetens wrote:
> > On Saturday 12 August 2006 23:21, Tobias Schwinger wrote:
[...]
> >>BTW: Not removing the class type (creating a function that takes the
> >> class context in form of a properly cv-qualified reference) is even
> >> simpler:
> >>
> >>   function_pointer<F>::type
> >>   // is 'bool (*)(X &,int)'       for F = 'bool (X::*)(int)'
> >>   // is 'bool (*)(X const &,int)' for F = 'bool (X::*)(int) const'
> >
> > Thanks, but I wanted the X& to be a pointer as well. OTOH, maybe I can
> > change my code to pass a reference to X.
>
>    function_pointer<F>::type
>
> is a shortcut for
>
>    function_pointer< components<F> >::type
>
> and 'components' has a second template parameter, an MPL Lambda Expression,
> that allows to change the way the class type is transformed (and so has
> 'parameter_types'):
>
>    function_pointer< components< F, add_pointer<_> >::type
>    // is 'bool (*)(X *,int)'       for F = 'bool (X::*)(int)'
>    // is 'bool (*)(X const *,int)' for F = 'bool (X::*)(int) const'
>
>
>    function_pointer< components< F, add_pointer< remove_cv<_> > >::type
>    // is 'bool (*)(X *,int)' for F = 'bool (X::*)(int)'
>    // is 'bool (*)(X *,int)' for F = 'bool (X::*)(int) const'
>

This is a complete killer-template. You are a genious. If this becomes the
'look-and-feel' interface of the whole library (instead of the 'tags'), it 
will be an example for many other meta programming libraries.

Peter
-- 
Peter Soetens -- FMTC -- <http://www.fmtc.be>