Reece Dunn wrote:
Robert Ramey wrote:
On the other hand - I don't see the motivation for including concepts in the core language. Haven't we been able to implement concept checking with the current facilities of the library? It seems to me that the main problem these days with the C++ language these days is that its too hard to write a correct compiler for it. Making the core language fancier will only make this problem worse.
Concepts in the language allow things that aren't currently possible with C++98. For example, standard algorithms of the form:
fn( Iterator first, Iterator last ) fn( Iterator first, Iterator last, Functor f )
cannot have overloads (in C++98) taking containers/ranges:
fn( Iterator first, Iterator last ) fn( Iterator first, Iterator last, Functor f ) fn( Range rng ) fn( Range rng, Functor f )
as the last overload is ambiguous. Concepts will allow this to be resolved as a Functor will not match the Iterator requirements :).
you can use enable_if on the latter and disable it the two types are the same. -Thorsten