Re: Lambda question (C++ 0x)
On 12 Feb., 03:05, "Thiago A." <thiago.ad...@gmail.com> wrote:
Considering this code:
template<class T>
void f(T t)
{
//typename t::Argument1 ??
//typename t::Argument2 ??
//typename t::Result ??
}
struct X;
struct Y;
f([] (X x, Y y) {
return false;
});
How can I find out in "f" the result and arguments types of the
lambda object?
You can't. Do you have an example where this is really needed? I'm not
really sure whether this is a missed opportunity or not. In case you
have good use cases where detecting those types is a major advantage,
you might want to propose some kind of compiler-supported type trait
class for this. Perhaps something like this:
template<class... Types> struct type_list;
template<class Functor> struct signature_traits
{
typedef type_list<???> parameter_types;
typedef ??? return_type;
};
Ideally this should work for function pointers, and functors that
expose their arity and types somehow (see std::unary_function,
std::binary_function, etc) as well and not just lambda objects.
Cheers,
SG
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