Re: [boost] determine first arg of callable

Subject: Re: [boost] determine first arg of callable
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2013-05-16 02:47:26

On Thu, May 16, 2013 at 10:25 AM, Nathan Ridge <zeratul976_at_[hidden]>wrote:

> > No, bind function object types do not have the argument types. These
> types
> > are not known until the function object is actually invoked. The only
> types
> > you will find is the bound function object type and bound argument values
> > types (and the latter may differ from the actual argument types, BTW).
>
> This is an aside, but is there a way, given the result of a bind(), to
> get the types of the bound argument values?
>

For boost::bind you can use visit_each [1] or decompose the bind_t template
type manually. Both ways are not quite documented, but it is doable. For
other bind implementations the code may differ but the same types should be
present in some form in the function object type.

[1] http://www.boost.org/doc/libs/release/libs/bind/bind_visitor.cpp