ConstantElement.cs

using System.Collections.Generic;
using System.Threading.Tasks;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Objects;
 
namespace Waher.Script.Model
{
    public class ConstantElement : ScriptLeafNode, IDifferentiable
    {
        private readonly IElement constant;
 
        public ConstantElement(IElement Constant, int Start, int Length, Expression Expression)
            : base(Start, Length, Expression)
        {
            this.constant = Constant;
        }
 
        public IElement Constant => this.constant;
 
        public override bool IsAsynchronous => false;
 
        public override IElement Evaluate(Variables Variables)
        {
            return this.constant;
        }
 
        public override Task<IElement> EvaluateAsync(Variables Variables)
        {
            return Task.FromResult<IElement>(this.constant);
        }
 
        public override PatternMatchResult PatternMatch(IElement CheckAgainst, Dictionary<string, IElement> AlreadyFound)
        {
            return this.constant.Equals(CheckAgainst) ? PatternMatchResult.Match : PatternMatchResult.NoMatch;
        }
 
        public ScriptNode Differentiate(string VariableName, Variables Variables)
        {
            return new ConstantElement(DoubleNumber.ZeroElement, this.Start, this.Length, this.Expression);
        }
 
        public string DefaultVariableName => null;
 
        public override bool Equals(object obj)
        {
            return obj is ConstantElement O &&
                this.constant.Equals(O.constant) &&
                base.Equals(obj);
        }
 
        public override int GetHashCode()
        {
            int Result = base.GetHashCode();
            Result ^= Result << 5 ^ this.constant.GetHashCode();
            return Result;
        }
    }
}