ObjectValue.cs

using System;
using System.Reflection;
using Waher.Script.Abstraction.Sets;
using Waher.Script.Abstraction.Elements;
using Waher.Events;
using System.Threading.Tasks;
 
namespace Waher.Script.Objects
{
    public sealed class ObjectValue : Element, IDisposableAsync
    {
        private static readonly ObjectValues associatedSet = new ObjectValues();
 
        private object value;
 
        public ObjectValue(object Value)
        {
            this.value = Value;
        }
 
        public object Value
        {
            get => this.value;
            set => this.value = value;
        }
 
        public override string ToString()
        {
            if (this.value is null)
                return "null";
            else
                return Expression.ToExpressionString(this.value);
        }
 
        public override ISet AssociatedSet
        {
            get { return associatedSet; }
        }
 
        public override object AssociatedObjectValue => this.value;
 
        public override bool Equals(object obj)
        {
            if (!(obj is IElement E))
                return false;
 
            object Obj = E.AssociatedObjectValue;
 
            if ((this.value is null) ^ (Obj is null))
                return false;
 
            if (this.value is null)
                return true;
 
            return this.value.Equals(Obj);
        }
 
        public override int GetHashCode()
        {
            if (this.value is null)
                return 0;
            else
                return this.value.GetHashCode();
        }
 
        public static readonly ObjectValue Null = new ObjectValue(null);
 
        public override bool TryConvertTo(Type DesiredType, out object Value)
        {
            TypeInfo TI = DesiredType.GetTypeInfo();
 
            if (this.value is null)
            {
                Value = null;
                return !TI.IsValueType || !(Nullable.GetUnderlyingType(DesiredType) is null);
            }
            else
            {
                if (TI.IsAssignableFrom(this.value.GetType().GetTypeInfo()))
                {
                    Value = this.value;
                    return true;
                }
                else if (TI.IsAssignableFrom(typeof(ObjectValue).GetTypeInfo()))
                {
                    Value = this;
                    return true;
                }
                else
                    return Expression.TryConvert(this.value, DesiredType, true, out Value);
            }
        }
 
        [Obsolete("Use DisposeAsync() instead.")]
        public void Dispose()
        {
            this.DisposeAsync().Wait();
        }
 
        public async Task DisposeAsync()
        {
            if (this.value is IDisposableAsync DAsync)
                await DAsync.DisposeAsync();
            else if (this.value is IDisposable D)
                D.Dispose();
        }
    }
}