Instantiating a class with different types at runtime

[ag0aep6g via Digitalmars-d-learn]

On 11/27/2016 09:52 PM, Marduk wrote:
>   class Example {
>
>     this(Type_left x, Type_right y) {
>       this.left = x;
>       this.right = y;
>     }
>
>     Type_left left;
>     Type_right right;
>
>   }
>
> Such that at runtime I can instantiate it with different types:
>
> new Example(int a, int b);
>
> new Example(int a, string b);

Turn Example into a template, and add a free function for nice construction:

----
class Example(Type_left, Type_right)
{
     /* ... as you had it ... */
}

Example!(L, R) makeExample(L, R)(L x, R y)
{
     return new Example!(L, R)(x, y);
}

void main()
{
     auto foo = makeExample(1, 2);
     auto bar = makeExample(3, "baz");
}
----

Note that Example is not a type, but a template. That means, foo and bar 
have different types, because their types are different instantiations 
of the Example template. You can define a common interface or (possibly 
abstract) base class.