ppoop solution

ppoop.cs

using System;
using System.Collections.Generic;

namespace ppoop
{
	// source: http://www.csis.pace.edu/~bergin/patterns/ppoop.html

	class MainClass
	{
		public static void Main (string[] args)
		{
			var osName = Get_operating_system_name ();
			var osCategory = Categorize_operating_system (osName);
			var msg = Qualify_operating_system (osCategory);
			Inform_user (msg);
		}


		static string Get_operating_system_name() {
			return System.Environment.OSVersion.VersionString;
		}


		enum OSCategories {
			Unix,
			Windows,
			Unknown
		}

		static OSCategories Categorize_operating_system(string osName) {
			if (osName.StartsWith("SunOS") || osName.StartsWith("Linux") || osName.StartsWith("Unix")) 
			{
				return OSCategories.Unix;
			} 
			else if (osName.StartsWith("Windows NT") || osName.StartsWith("Windows 95")) 
			{
				return OSCategories.Windows;
			} 
			else 
			{
				return OSCategories.Unknown;
			}
		}


		static Dictionary<OSCategories,string> OSQualifications =
			new Dictionary<OSCategories, string>{ 
			{OSCategories.Unix, "This is a UNIX box and therefore good."},
			{OSCategories.Windows, "This is a Windows box and therefore bad."},
			{OSCategories.Unknown, "This is not a box."}
		};

		static string Qualify_operating_system(OSCategories osCategory) {
			return OSQualifications [osCategory];
		}


		static void Inform_user(string message) {
			Console.WriteLine (message);
		}

	}
}

ppoop.fs

// source: http://www.csis.pace.edu/~bergin/patterns/ppoop.html

module Environment =
    let get_operating_system_name =
        System.Environment.OSVersion.VersionString;

    let inform_user msg =
        printfn "%s" msg


module Assessment =
    type OSCategories = Unix | Windows | Unknown

    let categorize_operating_system (name:string) =
        if name.StartsWith("SunOS") || name.StartsWith("Linux") || name.StartsWith("Unix")
        then Unix
        else if name.StartsWith("Windows NT") || name.StartsWith("Windows 95")
             then Windows
             else Unknown
    
    let qualify_operating_system = function
          Unix -> "This is a UNIX box and therefore good."
        | Windows -> "This is a Windows box and therefore bad."
        | Unknown -> "This is not a box."


[<EntryPoint>]
let main _ = 
    Environment.get_operating_system_name
    |> Assessment.categorize_operating_system
    |> Assessment.qualify_operating_system
    |> Environment.inform_user

    0