Question

I m trying to create a type that has multiple type parameters. I know how to make a type with one parameter:

type  a foo =  a * int

But I need to have two parameters, so that I can parameterize the int part. How can I do this?

Answer 1

The way to do this is:

type ( a,  b) foo =  a *  b

Type parameters aren t curried, so you need to provide them in tuple form as a single parameter. A good example of this is the Hashtbl module:

type ( a,  b) t 
The type of hash tables from type a to type b.

Answer 2

# type ( a, b) couple = a * b ;;

For instance...