Template constraint and specializations

[Andrej Mitrovic]

On 3/23/12, Ed McCardell <edmccard at hotmail.com> wrote:
> Is there a way to write a template constraint that matches any
> specialization of a given type?

Nope. But there are simple workarounds:

class Foo(bool feature1, bool feature2) { enum _isFoo = true; }

template isFoo(T) {
    enum bool isFoo = __traits(hasMember, T, "_isFoo");
}

void useFoo(T)(T foo)
   if (isFoo!T)
{
   // call methods of foo that don't change based on feature1/feature2
}

void main()
{
    Foo!(true, false) foo;
    useFoo(foo);
}