Proposal to add 'Elements of Programming' Concepts to std.traits

[Philippe Sigaud]

On Sat, Jun 16, 2012 at 9:22 PM, bearophile <bearophileHUGS at lycos.com> wrote:

> I see. is that semantically different from this (beside being shorter)?
>
> struct NoZero {
>    int value;
>    this(int x) { value = x; }
>    alias value this;
>    invariant() { assert(value != 0); }
> }
> void main() {
>    auto a = NoZero(5);
>    auto b = NoZero(0);
> }

The invariant isn't invoked through alias this, it seems:

void main() {
   auto a = NoZero(5);
   a = 0; // compiles and runs happily
}