On 2011-09-15 16:46, Andrej Mitrovic wrote:
struct Foo(T = int) {}

void main()
{
     Foo foo;  // fail
     Foo!() bar;  // ok
}

It would be very convenient to be able to default to one type like this.

For example, in CairoD there's a Point structure which takes doubles
as its storage type, and then there's PointInt that takes ints. The
reason they're not both a template Point() that takes a type argument
is because in most cases the user will use the Point structure with
doubles, and only in rare cases Point with ints. So to simplify code
one doesn't have to write Point!double in all of their code, but
simply Point.

If the bang syntax wasn't required in presence of default arguments
then these workarounds wouldn't be needed.

I've wondered the same thing, why this doesn't work:

template Foo (T = int) {}

mixin Foo;

But this works:

template Foo () {}

mixin Foo;

--
/Jacob Carlborg

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