Use list cons operator (a :: b) as a function

Question

F# lets you turn operators into functions by surrounding them with ( ): for instance, (+) is of type int -> int -> int

Answer 1

:: and [] can both be represented by List<_>.Cons and List<_>.Empty respectively. Keep in mind though that the former takes a tuple as an argument. These are here so lists can be created in languages other than F#.

> List.Cons(4, List.Empty);;
val it : int list = [4]

> 4::[];;
val it : int list = [4]

> List.Cons(4, List.Empty);;
val it : int list = [4]

> List.Cons;;
val it : 'a * 'a list -> 'a list =  //'

> List.Empty;;
val it : int list = []