OCaml: bound expressions v. functions

Question

Here we have a function definition:

let f x = x + 3;;

Here is an expression:

let g = 4;;

Could g just be thought of as constant function that takes no arguments? Is there any difference?

Answer 1

Yes - From a totally functional point of view (like practised in Haskell), everything is a function (Really everything).

And since a purely-functional language disallows any kind of change, this definition does not bear any contradictions.

Is there any difference?

Well, OCaml is not purely-functional. This means the functions are allowed to perform side-effects which differs a bit from the definition of a constant value.

This code (F# here - but quite similar in Caml) would be perfectly valid.

let name = 
    Console.Write("Enter your Name: ")
    Console.ReadLine()