MaxEvaluator.cs

using Waher.Script.Abstraction.Elements;
using Waher.Script.Abstraction.Sets;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Script.Functions.Vectors
{
    public class MaxEvaluator : UnaryIterativeEvaluator
    {
        private IElement max = null;
        private IOrderedSet maxSet = null;
        private double? doubleMax = null;
        private bool isDouble = true;
        private bool first = true;
 
        public MaxEvaluator(Max Node)
            : base(Node.Argument)
        {
        }
 
        public override void RestartEvaluator()
        {
            this.max = null;
            this.doubleMax = null;
            this.isDouble = true;
            this.first = true;
        }
 
        public override void AggregateElement(IElement Element)
        {
            if (this.first)
            {
                this.first = false;
 
                if (Element is DoubleNumber D)
                {
                    this.doubleMax = D.Value;
                    this.max = D;
                    this.maxSet = (IOrderedSet)D.AssociatedSet;
                }
                else
                {
                    if (!(Element.AssociatedSet is IOrderedSet S))
                        throw new OperandComparisonScriptException(this.Node);
 
                    this.isDouble = false;
                    this.max = Element;
                    this.maxSet = S;
                }
            }
            else if (this.isDouble && Element is DoubleNumber D)
            {
                double d = D.Value;
 
                if (d > this.doubleMax)
                    this.doubleMax = d;
            }
            else if (this.max is null || this.maxSet.Compare(this.max, Element) < 0)
            {
                if (!(Element.AssociatedSet is IOrderedSet S))
                    throw new OperandComparisonScriptException(this.Node);
 
                this.max = Element;
                this.maxSet = S;
                this.isDouble = false;
            }
        }
 
        public override IElement GetAggregatedResult()
        {
            if (this.isDouble)
            {
                if (this.doubleMax.HasValue)
                    return new DoubleNumber(this.doubleMax.Value);
                else
                    return ObjectValue.Null;
            }
            else
                return this.max ?? ObjectValue.Null;
        }
    }
}