Ellery Newcomer wrote:
Okay, let me rephrase that:
When you have a <something> preceded by a colon in a template value
parameter, what are its semantics? Is it the same as a default parameter
value? Is it some sort of constraining expression? Is it a vestige?
void foo(T : int)(T value)
{
// value is implicitly convertible to int
}
It can do some pattern matching:
void foo(T : V[U], V, U)(T dictionary)
{
// I have an associative array
}
In D2, it's usually going to be easier to use constraints:
template foo(T) if (isAssociativeArray!T) {}
