Island.StandardLib/EXTS/EValue.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EXTS
{
    public class EValue
    {
        public ETypeInstance Instance;
        public bool Defined => Instance != null;

        public EValue(ETypeInstance instance = null) => Instance = instance;

        internal T As<T>() where T : ETypeInstance => Instance as T;
    }
}