Simple and lightweight C# REPL with Mono.CSharp

Recently I needed a small C# REPL because I wanted to test some code on a computer where I couldn't install Visual Studio and the code I wanted to test used a lot of (Service) references so I couldn't use something like LINQPad. I first started with Roslyn but had some issues with using it from Visual Studio 2012 and as I didn't want to spend too much time on this problem I went for Mono.CSharp.Evaluator. Mono.CSharp can be installed with npm: Install-Package Mono.CSharp and only adds one reference which is a nice side-effect of using Mono.CSharp instead of the Roslyn scripting API.

Here is the full code (github) of my simple REPL. If you end a statement with ';' then it will run without returning an output, use this when you want to create objects . If you omit the ';' then the expression is evaluated and the result printed. Note that I added a reference to my program to the evaluator in order to be able to call the Factorial function. Also fon't to forget to run the necesssary Using statements.

// Install-Package Mono.CSharp
using System;
using System.Reflection;
using Mono.CSharp;

namespace SimpleREPL
{
  public class ExtraMath
  {
    public static int Factorial(int n)
    {
      // naive implementation but fast enough for small n
      int result = 1;
      for (int i = 1; i <= n; i++)
      {
        result *= i;
      }
      return result;
    }
  }

  internal class Program
  {
    private static void Main(string[] args)
    {
      Console.WriteLine("Starting Simple C# REPL, enter q to quit");
      var evaluator = new Evaluator(new CompilerContext(
        new CompilerSettings(),
        new ConsoleReportPrinter()));
      evaluator.ReferenceAssembly(Assembly.GetExecutingAssembly());
      evaluator.Run("using System;");
      evaluator.Run("using SimpleREPL;");
      while (true)
      {
        Console.Write("> ");
        var input = Console.ReadLine();
        input = input.TrimStart('>', ' ');
        if (input.ToLower() == "q")
        {
          return;
        }
        try
        {
          if (input.EndsWith(";"))
          {
            evaluator.Run(input);
          }
          else
          {
            var output = evaluator.Evaluate(input);
            Console.WriteLine(output);
          }
        }
        catch
        {
          Console.WriteLine("Error in input");
        }
      }
    }
  }
}