Re: How to do "inheritance" in D structs

[Jacob Carlborg via Digitalmars-d-learn]

On 2016-10-12 03:22, lobo wrote:
Hi,
I'm coming from C++ and wondered if the pattern below has an equivalent
in D using structs. I could just use classes and leave it up to the
caller to use scoped! as well but I'm not sure how that will play out
when others start using my lib.

Thanks,
lobo


module A;

class Base1 {
    int ival = 42;
}
class Base2 {
    int ival = 84;
}

module B;

class S(ABase) : ABase {
    string sval = "hello";
}

module C;

import A;
import B;

void main() {
    auto s= scoped!(S!Base1); // scoped!(S!Base2)
}

Depending on what you need, any alternative to structs and "alias this" 
would be to use structs with template mixins [1]:

mixin template Base1()
{
    int ival = 42;
}

struct S(ABase)
{
    mixin ABase;
}

What's in the struct will take precedence of what's in the template 
mixin. It's also possible to mix in several templates.

[1] http://dlang.org/spec/template-mixin.html

--
/Jacob Carlborg