I understand. Sure thing, VM.Eval("your code") returns a value if one is produced. if (vm.Eval("1:2") is Value v and v.Type == Libs.Core.Pair) { Console

I understand. Sure thing, VM.Eval("your code") returns a value if one is produced. if (vm.Eval("1:2") is Value v and v.Type == Libs.Core.Pair) { Console.WriteLine("Pair: " + v.Cast(Libs.Core.Pair)); } Have a look in the main Program.cs to see how to get a VM up and running.