interpret : TurtlePar -> List String -> List (Svg.Svg msg)
interpret turtlePar commands =
    if isEmpty commands then
        [ drawTurtle first (first turtlePar) first (second turtlePar) second turtlePar ]
    else
        let
            cmdType : String -> String
            cmdType str =
                Maybe.withDefault "" (head (split " " str))

            cmdArg : String -> String
            cmdArg str =
                Maybe.withDefault "" (head (Maybe.withDefault [] (tail (split " " str))))

            posTrans : TurtlePar -> String -> String -> TurtlePar
            posTrans prevTurtle cmdTip cmdOp =
                if cmdTip == "F" then
                    ( ( round (toFloat (first (first prevTurtle)) + (cos (toFloat (second prevTurtle)) * toFloat cmdOp)), round (toFloat (second (first prevTurtle)) + (sin (toFloat (second prevTurtle)) * toFloat cmdOp)) ), second prevTurtle )
                else if cmdTip == "R" then
                    ( first prevTurtle, (second prevTurtle + toInt cmdOp) % 360 )
                else
                    ( ( -1, -1 ), -1 )

            calcPoint : TurtlePar -> String
            calcPoint turtle =
                toString (first (first turtle)) ++ "," ++ toString (second (first turtle))
        in
        if cmdTip == "F" then
            [ Svg.polyline [ points (calcPoint turtle ++ " " ++ calcPoint (posTrans turtlePar cmdType commands cmdArg commands)), fill "none", stroke "black" ] [] ] ++ interpret (posTrans turtlePar cmdType commands cmdArg commands) (Maybe.withDefault [] (tail commands))
        else if cmdTip == "R" then
            interpret (posTrans turtlePar cmdType commands cmdArg commands) (Maybe.withDefault [] (tail commands))
        else
            []