SFINAE question 2

[Onay Urfalioglu]

On 08/22/2012 11:01 PM, Jonathan Wakely wrote:
> template<typename T>
> struct HasRandomAccessOp {
>      typedef decltype(std::declval<T>()[0]) test_type;
> };
>
> template<typename T, typename T_VECTOR,
>           typename = typename HasRandomAccessOp<T_VECTOR>::test_type>
> int operator*(const T &l, const T_VECTOR &r) {
>      return 1;
> }
Hi Jonathan,

yes, this works as expected ;-)

I wonder whether it is possible to overload the operator*() to have two 
versions:
   - one for all T_VECTOR - types having operator[]
   - one for all T_VECTOR - types not having operator[] but providing 
say a forward iterator, like std::list

(This is just a toy requirement, I am aware that one can implement this 
in other ways too...)

You see I am painfully missing some C++11 concepts functionality here...

Cheers,
onay