Re: [boost] [function_types] is there an equivalent for functors?

Subject: Re: [boost] [function_types] is there an equivalent for functors?
From: Jeffrey Lee Hellrung, Jr. (jhellrung_at_[hidden])
Date: 2010-07-05 14:50:22

On 7/5/2010 11:33 AM, Edd Dawson wrote:
> On 7/5/2010 6:59 PM, Jeffrey Lee Hellrung, Jr. wrote:
>> On 7/5/2010 10:46 AM, Edd Dawson wrote:
>>> Hi all,
>>>
>>> I'm looking for code that does what
>>> boost::function_types::parameter_types does but for functors. Support
>>> for things such as boost::bind/lambda/function/signals(1&2)/etc and the
>>> standard binders and adaptors would be nice.
>
>> If you want restrict yourself to monomorphic function objects, then it
>> might be possible, but I don't know of a generic way to obtain the
>> information you're seeking.
>
> Ah yes, I didn't mean to imply that I was seeking a truly generic
> solution. A "sanctioned" collection of template specializations for
> common functor types would be fine.

You can create a trait which exposes the parameter and return types and 
specialize it for the function objects you'd be interested in using.  E.g.,

template< class T > struct fn_traits;

template< ... > struct fn_traits< boost::detail::binder< ... > > { ... };

Not the most robust solution (in that you may be relying on 
implementation details), but it might get you far enough...

[...]
> Without having a database of types upfront and employing an exponential
> algorithm, can_be_called is probably not going to get me what I want,
> right?

I agree, I don't think it helps in this case.

- Jeff