Function pipe operator

Write an infix operator (|>) that behaves like the Unix pipe operator, i.e. it allows you to write function applications in a left-to-right manner.

For example, given the functions:

let double x = x * 2;;
let square x = x * x;;

the pipe operator must enojoy the following equalities:

3 |> double = double 3
3 |> double |> square = square (double 3) 
3 |> double |> square |> double = double (square (double 3))

The function must have the following type:

(|>) : 'a -> ('a -> 'b) -> 'b

Here are some unit tests:

let double x = x * 2;;
let square x = x * x;;

assert(3 |> double = 6);;
assert(3 |> square = 9);;
assert(3 |> square |> double = 18);;
assert(3 |> double |> square = 36);;
assert(3 |> double |> square |> double = 72);;
assert("hello" |> String.trim |> String.uppercase_ascii = "HELLO");;