ext.cs

using System;
using System.IO.Ports;
using System.Threading;
using System.Globalization;

namespace Terminal
{
  static class Program
	{
		static void Main(string[] s)
		{
			while (true)
			{
				var t = Console.ReadLine();
				int i;
				double j;
				if (t.To(out i))
					Console.WriteLine("int: " + i);
				if (t.To(out j))
					Console.WriteLine("float: " + j);
			}
		}

		public static bool To<T>(this string value, out T result)
		{
			result = default(T);
			var convertor = System.ComponentModel.TypeDescriptor.GetConverter(typeof(T));
			if (convertor == null || !convertor.IsValid(value))
			{
				return false;
			}
			result = (T)convertor.ConvertFrom(value);
			return true;
		}
		
		public static T With<T>(this T self, Func<T> action)
		{
			action(self);
			return self;
		}
	}
}