CODEWITHSUNDEEP
ocaml
ragesalmon
ragesalmon

Reputation: 637

Function signature as type in OCaml

Is there a way to declare something like

type do = ('a -> 'b)

in OCaml? Specifically, to declare a function signature as a type

Upvotes: 0

Views: 303

Answers (1)

Jeffrey Scofield
Jeffrey Scofield

Reputation: 66808

For free types 'a and 'b,'a -> 'b is not the type of any well behaved OCaml function, because it requires the function to produce a value of an arbitrary type.

So, you can't give a name to a type with unbound parameters:

# type uabfun = 'a -> 'b
Error: Unbound type parameter 'a

If you use specific types, there's no problem giving it a name:

# type iifun = int -> int;;
type iifun = int -> int

If type types 'a and 'b are parameters (rather than being free), there is also no problem:

# type ('a, 'b) abfun = 'a -> 'b;;
type ('a, 'b) abfun = 'a -> 'b

Upvotes: 2

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