Reverse Polish notation

gistfile1.fs

let solveRPN expression =  
    let foldingFunction stack item = 
        match (stack,item) with
            | (x::y::xs,"*") -> x * y :: xs
            | (x::y::xs,"+") -> x + y :: xs
            | (x::y::xs,"-") -> y - x :: xs
            | (s,o) -> int o :: s
    let words (i:string) = i.Split(' ') |> List.ofArray
    words expression 
        |> List.fold foldingFunction []
        |> List.head

solveRPN "10 4 3 + 2 * -" |> Console.WriteLine