let pushNum i =
    match i with
    | IntVal x -> "ldc.i4.s " + string x
    | _        -> failwith "Syntax error"


let rec compile expr =
    match expr with
    | ConstInt i                  -> pushNum (IntVal i)
    | PrimOp ("+", lOper, rOper)  -> evalNumericExpr (+) lOper rOper
    //| PrimOp ("-", lOper, rOper)  -> evalNumericExpr (-) lOper rOper
    //| PrimOp ("*", lOper, rOper)  -> evalNumericExpr (*) lOper rOper
    //| PrimOp ("/", lOper, rOper)  -> evalNumericExpr (/) lOper rOper
    //| PrimOp ("%", lOper, rOper)  -> evalNumericExpr (%) lOper rOper
    | _                 -> failwith "Syntax error"

and evalNumericExpr op lOper rOper =
    let left = compile lOper
    let right = compile rOper
    match (op) with
    | (+) ->  "ADD"
    | _   -> failwith "Syntax error"