Can someone explain this error?
Sean Kelly
sean at invisibleduck.org
Tue Sep 23 16:56:55 PDT 2008
== Quote from Jarrett Billingsley (jarrett.billingsley at gmail.com)'s article
> On Tue, Sep 23, 2008 at 7:26 PM, Sean Kelly <sean at invisibleduck.org> wrote:
> > class C
> > {
> > this() {}
> > this( int x, int y ) {}
> > }
> >
> > void main()
> > {
> > auto c = alloc!(C);
> > auto d = alloc!(C)( 1, 2 );
> > }
> >
> > T alloc(T, Params ...)( Params params )
> > {
> > return new T( params );
> > }
> >
> > $ dmd test
> > test.d(10): Error: expected 0 arguments, not 2
> >
> You cannot partially specify a template. alloc!(C) means that
> Params... is the empty tuple: hence, 0 arguments expected.
> template alloc(T)
> {
> T alloc(Params ...)( Params params )
> {
> return new T( params );
> }
> }
> does the trick, but requires you to call it with empty parens in the
> 0-param case (like "alloc!(C)()").
I'm pretty sure it's possible to partially specify a template. Consider:
void main()
{
fn!(int)( 5 );
}
void fn(A, B)( B b ) {}
This works just fine, but if I change the function declaration to:
void fn(A, B ...)( B b ) {}
it fails. Are variadic templates a special case?
Sean
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