This kind of code compiles and runs extremely slow.

[RickyYCheng]

I've learned a "skill" due to this question.
codewars: A Simple Postfix Language
And my answer is:

let begin_ f = f []
let push s n f = f (n :: s)
let add (a :: b :: s) cont = cont ((a + b) :: s)
let end_ = List.head

then we can call begin_ push 1 push 2 add end_ in F#!

In Haskell version, they advise:

 The inferred type of a basic implementation is exponential in size to the expression. This causes type inference to take too long.
 Hint: Use a typeclass
 Hint: http://chrisdone.com/posts/haskell-constraint-trick

for this kind of code, the F# version will be slow too.

bad = begin push 1 push 1 push 1 push 1 push 1 push 1 push 1 push 1 push 1
        add add add add add add add add end

my quetsion is why do our program will run slowly?
and if you just use the pipeline |> such as

let begin_ = [] 
let push s n = s::n 
let add (a::b::s) = (a+b)::s
let end_ = List.head

it will have a very beautiful performance.