gistfile1.txt

  	public static void ComplexAST()
		{
			var a = Expression.Parameter(typeof(long), "a");
			var b = Expression.Parameter(typeof(long), "b");

			var test = Expression.Variable(typeof(long), "test");
			var i = Expression.Variable(typeof(long), "i");
			var start = Expression.Label();
			var end = Expression.Label();

			var check = Expression.GreaterThanOrEqual (i, Expression.Multiply (a, b));

			var block = Expression.Block (
				new ParameterExpression[] { test, i },
				Expression.Assign (test, Expression.Constant (2L)),
				Expression.Assign (i, Expression.Constant (1L)),
				Expression.Label (start),
				Expression.IfThen (check, Expression.Goto (end)),
				Expression.MultiplyAssign (test, i),
				Expression.PreIncrementAssign (i),
				Expression.Goto (start),
				Expression.Label(end),
				test);

			var lambda = Expression.Lambda<Func<long, long, long>>(block, new ParameterExpression[] { a, b });
			var func = lambda.Compile();

			var ret = func(3, 4);
			Console.WriteLine(ret);
		}

		public static void Complex()
		{
			Func<int,int,long> lambda = (a,b) => {
				long test = 2;
				for (int i = 1; i < a * b; i++)
				{
					test *= i;
				}
				return test;
			};

			var ret = lambda(3, 4);
			Console.WriteLine(ret);
		}