Rebind template(bug?)
Lodovico Giaretta via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Sun Aug 21 12:46:03 PDT 2016
On Sunday, 21 August 2016 at 19:42:08 UTC, Lodovico Giaretta
wrote:
> On Sunday, 21 August 2016 at 19:29:26 UTC, Engine Machine wrote:
>> [...]
>
> The problem of this code has nothing to do with aliases. They
> work correctly. The problem is variable shadowing. In the
> following code, Child has two x variables, one of which is only
> accessible from a Parent reference, the other only from a Child
> reference.
>
> class Parent
> {
> int x;
> }
> class Child: Parent
> {
> int x; // this shadows Parent.x
> int y;
> }
>
> void main()
> {
> Child child = new Child();
> Parent parent = child;
>
> child.x = child.y = 3;
> parent.x = 2;
>
> assert(child.x == 3);
> assert((cast(Child)parent).x == 3);
> assert((cast(Parent)child).x == 2);
>
> assert(parent is child); // same object (remember that a
> class is already a pointer);
> assert(&parent != &child); // but there are two different
> pointers on the stack (pointing to the same object)
> }
A patch to your code that makes it work, with the parts not
displayed unchanged:
class base
{
int x;
}
class T(A...) : Rebind!(T!A, EraseLast!A)
{
static if(A[$-1] == "Animal")
int y;
else static if (A[$-1] == "Dog")
int z;
else static if (A[$-1] == "Pug")
int s;
}
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