On Monday, 14 August 2017 at 15:20:28 UTC, Steven Schveighoffer
wrote:
On 8/14/17 9:48 AM, Dominikus Dittes Scherkl wrote:
> uint foo(T)(Unqual!T n) // first try
> {
> ++n; // modify should be possible
> return 42;
> }
> Any ideas what I need to do to make this work?
This isn't exactly supported. Implicit Function Template
Instantiation (IFTI) will deduce the parameters to be the types
that you pass in. You can't deduce them and then change the
parameter types. This is a limitation of IFTI that I have
struggled with in the past.
A little unfortunate, because I would consider this the standard
usecase.
You only overload functions if they do something special with
const or shared or immutable parameters, but for templates you
get a different implementation for these all the time, and you
didn't even have a chance to avoid that useless code-bloat? What
a pitty.
What you can do, is:
auto foo(T)(T n) if (is(T == Unqual!T))
{
// normal implementation
}
auto foo(T)(T n) if (!is(T == Unqual!T) &&
isImplicitlyConvertible!(T, Unqual!T))
{
return foo!(Unqual!T)(n);
}
Ok, I'll try that out.
