scala: inheriting base class from type parameter

Question

Is that possible to create a type class based on type parameter by inheriting type parameter like in the code below?

I do suspect that this is fundamentally not possible as this is a scala limitation as functional language...

But if possible what I have to change in the code below??

class MyInt[T : Numeric]  extends T  {

}

Michael Zajac · Accepted Answer · 2016-04-15 19:17:13Z

1

It's not possible. You can extend a class (traits included), but you cannot extend a type, and T is a type.

Even if it were possible, what would it then mean to have MyInt[Int] (which is final), or MyInt[List[String]] (which is not a class) ? It would get quite complicated for the compiler very quickly.

answered Apr 15, 2016 at 19:17

Michael Zajac

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4 Comments

Pavel Over a year ago

So this is a language limitation and I would assume general limitation for functional programming ???

Michael Zajac Over a year ago

It's a language limitation. It doesn't have anything to do with functional programming. I don't know of any programming language that can do exactly what you are asking.

Travis Brown Over a year ago

@PavelOliynyk The intersection of FP and subtyping is small and weird—in most functional languages the question wouldn't even make sense. :)

Pavel Over a year ago

well, just checked. It looks like this is not possible in other languages as well. thank you

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