01-OOTurtle.fsx

(* ======================================
01-OOTurtle.fsx

Part of "Thirteen ways of looking at a turtle"
Related blog post: http://fsharpforfunandprofit.com/posts/13-ways-of-looking-at-a-turtle/
======================================

Way #1: Simple OO -- a class with mutable state

In this design, a simple OO class represents the turtle,
and the client talks to the turtle directly.

====================================== *)

#load "Common.fsx"

open System
open Common

// ======================================
// OO Turtle
// ======================================

// see code in this file
#load "OOTurtleLib.fsx"

// ======================================
// OO Turtle Client
// ======================================

module OOTurtleClient = 
    open OOTurtleLib

    /// Function to log a message
    let log message =
        printfn "%s" message 

    let drawTriangle() = 
        let turtle = Turtle(log)
        turtle.Move 100.0 
        turtle.Turn 120.0<Degrees>
        turtle.Move 100.0 
        turtle.Turn 120.0<Degrees>
        turtle.Move 100.0
        turtle.Turn 120.0<Degrees>
        // back home at (0,0) with angle 0
            
    let drawThreeLines() = 
        let turtle = Turtle(log)
        // draw black line 
        turtle.PenDown()
        turtle.SetColor Black
        turtle.Move 100.0 
        // move without drawing
        turtle.PenUp()
        turtle.Turn 90.0<Degrees>
        turtle.Move 100.0 
        turtle.Turn 90.0<Degrees>
        // draw red line 
        turtle.PenDown()
        turtle.SetColor Red
        turtle.Move 100.0
        // move without drawing
        turtle.PenUp()
        turtle.Turn 90.0<Degrees>
        turtle.Move 100.0 
        turtle.Turn 90.0<Degrees>
        // back home at (0,0) with angle 0
        // draw diagonal blue line 
        turtle.PenDown()
        turtle.SetColor Blue
        turtle.Turn 45.0<Degrees>
        turtle.Move 100.0

    let drawPolygon n = 
        let angle = 180.0 - (360.0/float n) 
        let angleDegrees = angle * 1.0<Degrees>
        let turtle = Turtle(log)

        // define a function that draws one side
        let drawOneSide() = 
            turtle.Move 100.0 
            turtle.Turn angleDegrees 

        // repeat for all sides
        for i in [1..n] do
            drawOneSide()

// ======================================
// OO Turtle tests
// ======================================

(*
OOTurtleClient.drawTriangle() 
OOTurtleClient.drawThreeLines() 
OOTurtleClient.drawPolygon 4 
*)