// Learn more about F# at http://fsharp.org
// See the 'F# Tutorial' project for more help.

type instruction =
    | ADD
    | SUB
    | MUL
    | SQR
    | DIV
    | PUSH of float

type stack = float list

exception BLEDNY_PROGRAM of (instruction * stack)

let intInstr (x, y) =
    match x, y with
    | ADD, a::b::ys -> (b + a) :: ys : stack
    | SUB, a::b::ys -> (b - a) :: ys
    | MUL, a::b::ys -> (b * a) :: ys
    | DIV, a::b::ys -> try
                        (b / a) :: ys with
                        | :? System.DivideByZeroException as a -> printfn "Dzielenie przez zero: %s" a.Message; ys;
    | SQR, a::ys -> (a * a) :: ys
    | PUSH x, ys -> x::ys
    | _, _ -> raise (BLEDNY_PROGRAM(x, y));

let wypisz_instr = function
    | ( PUSH x) -> "PUSH " + System.Convert.ToString(x)
    | ( SQR ) -> " SQR "
    | ( ADD ) -> " ADD "
    | ( SUB ) -> " SUB "
    | ( MUL ) -> " MUL ";

let intpProg(is) =
    let rec iPS = function
        | ([],x::xs) -> x
        | (i::is, xs) -> iPS(is, intInstr(i, xs))

    iPS(is, [])

[<EntryPoint>]
let main argv =
    //let i1 = PUSH 3.0;
    //let i2 = PUSH 4.0;
    //let i3 = SUB;
    //let i4 = PUSH 2.0;
    //let i5 = MUL;
    //let stos:stack = [];
    //let stos1 = try intInstr(SQR, stos) with BLEDNY_PROGRAM(a, b) ->
    //                                         (
    //                                            printf "Wyjątek: Błędne wykonanie programu\nOperand: %A, Stos: %A" a b;
    //                                            b
    //                                            );
    ////let stos2 = intInstr(ADD, stos1);
    //let stos1 = intInstr(i1, stos);
    //let stos2 = intInstr(i2, stos1);
    //let stos3 = intInstr(i3, stos2);
    //let stos4 = intInstr(i4, stos3);
    //let stos5 = intInstr(i5, stos4);
    let il1 = [PUSH 3.0; PUSH 0.0; DIV]
    let il2 = [PUSH 3.0; PUSH 4.0; ADD; PUSH 2.0];
    let il3 = [PUSH 3.0; PUSH 4.0; ADD; MUL];

    //let w = intpProg(il3)
    //printfn "%A" (wypisz_instr MUL)

    printfn "%A" (intpProg il1);
    0 // return an integer exit code