Instantiating a class with different types at runtime
ag0aep6g via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Sun Nov 27 13:06:58 PST 2016
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.
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