Comment by orthoxerox
10 hours ago
Third paragraph from the top:
> unions enable designs that traditional hierarchies can’t express, composing any combination of existing types into a single, compiler-verified contract.
10 hours ago
Third paragraph from the top:
> unions enable designs that traditional hierarchies can’t express, composing any combination of existing types into a single, compiler-verified contract.
It's very unclear which you mean by that.
To me that "compiler-verified" maps to "sealed", not "on the fly". Probably.
Their example is:
public union Pet(Cat, Dog, Bird);
Pet pet = new Cat("Whiskers");
- the union type is declared upfront, as is usually the case in c#. And the types that it contains are a fixed set in that declaration. Meaning "sealed" ?
OK then, what is the opposite of this, the adhoc union?
I don’t know for sure, but I’m guessing something like
(Dog, Cat) pet = new Cat();
So without defining the union with an explicit name beforehand.
1 reply →
I don't follow the question. Maybe define the term that you are using?
1 reply →
I mean that Cat, Dog and Bird don't have to inherit from the union, you can declare a union of completely random types, as opposed to saying "Animal has three subtypes, no more, no less", which is what F# does more or less.