PowerShell StreamHost implementation in c#

/*
 * A simple PowerShell StreamHost
 *
 * Copyright (c) 2012 Michael 'mihi' Schierl
 *
 * Used to run PowerShell where no Console is available (like in embedded consoles or via telnet)
 * Note that the PowerShell experience will be limited (no dynamic prompts, no scrolling, etc.)
 */
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Management.Automation;
using System.Management.Automation.Host;
using System.Management.Automation.Runspaces;
using System.Threading;

namespace StreamHost
{
    class ConsoleUI : PSHostUserInterface
    {
        public override Dictionary<string, PSObject> Prompt(string caption, string message, Collection<FieldDescription> descriptions)
        {
            return null;
        }

        public override int PromptForChoice(string caption, string message, Collection<ChoiceDescription> choices, int defaultChoice)
        {
            return -1;
        }

        public override PSCredential PromptForCredential(string caption, string message, string userName, string targetName, PSCredentialTypes allowedCredentialTypes, PSCredentialUIOptions options)
        {
            return null;
        }

        public override PSCredential PromptForCredential(string caption, string message, string userName, string targetName)
        {
            return null;
        }

        public override PSHostRawUserInterface RawUI
        {
            get { return null; }
        }

        public override string ReadLine()
        {
            return Console.In.ReadLine();
        }

        public override System.Security.SecureString ReadLineAsSecureString()
        {
            return null;
        }

        public override void Write(ConsoleColor foregroundColor, ConsoleColor backgroundColor, string value)
        {
            Console.Out.Write(value);
        }

        public override void Write(string value)
        {
            Console.Out.Write(value);
        }

        public override void WriteDebugLine(string message)
        {
            Console.Error.WriteLine(message);
        }

        public override void WriteErrorLine(string value)
        {
            Console.Error.WriteLine(value);
        }

        public override void WriteLine(string value)
        {
            Console.Out.WriteLine(value);
        }

        public override void WriteProgress(long sourceId, ProgressRecord record)
        {
        }

        public override void WriteVerboseLine(string message)
        {
            Console.Error.WriteLine(message);
        }

        public override void WriteWarningLine(string message)
        {
            Console.Error.WriteLine(message);
        }
    }
    class StreamHost : PSHost
    {
        ConsoleUI ui = new ConsoleUI();
        public int? e = null;
        Guid id = Guid.NewGuid();

        public override System.Globalization.CultureInfo CurrentCulture
        {
            get { return Thread.CurrentThread.CurrentCulture; }
        }

        public override System.Globalization.CultureInfo CurrentUICulture
        {
            get { return Thread.CurrentThread.CurrentUICulture; }
        }

        public override void EnterNestedPrompt()
        {
            throw new NotImplementedException();
        }

        public override void ExitNestedPrompt()
        {
            throw new NotImplementedException();
        }

        public override Guid InstanceId
        {
            get { return id; }
        }

        public override string Name
        {
            get { return "StreamHost"; }
        }

        public override void NotifyBeginApplication()
        {
        }

        public override void NotifyEndApplication()
        {
        }
        public override void SetShouldExit(int exitCode)
        {
            e = exitCode;
        }

        public override PSHostUserInterface UI
        {
            get { return ui; }
        }

        public override Version Version
        {
            get { return new Version(1, 0); }
        }
    }
    static class Program
    {
        static void Main(string[] args)
        {
            StreamHost h = new StreamHost();
            Runspace r = RunspaceFactory.CreateRunspace(h);
            r.Open();
            PowerShell p = PowerShell.Create();
            p.Runspace = r;
            while (h.e == null)
            {
                Console.Out.Write(r.CreatePipeline("prompt").Invoke()[0]);
                p.Commands.Clear();
                p.AddScript(Console.In.ReadLine()).AddCommand("out-default");
                p.Commands.Commands[0].MergeMyResults(PipelineResultTypes.Error, PipelineResultTypes.Output);
                p.Invoke();
            }
            p.Dispose();
            Environment.Exit(h.e.Value);
        }
    }
}