PopLast.cs

using System.Collections.Generic;
using Waher.Runtime.Collections;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Script.Functions.Vectors
{
    public class PopLast : FunctionOneVectorVariable
    {
        private readonly VariableReference reference;
 
        public PopLast(ScriptNode Argument, int Start, int Length, Expression Expression)
            : base(Argument, Start, Length, Expression)
        {
            this.reference = Argument as VariableReference;
        }
 
        public override string FunctionName => nameof(PopLast);
 
        public override IElement EvaluateVector(IVector Argument, Variables Variables)
        {
            int c = Argument.Dimension;
            if (c == 0)
                return ObjectValue.Null;
 
            IElement Result = Argument.GetElement(c - 1);
 
            if (!(this.reference is null))
            {
                ICollection<IElement> Elements = Argument.VectorElements;
                ChunkedList<IElement> Elements2 = new ChunkedList<IElement>();
 
                foreach (IElement E in Elements)
                {
                    if (--c > 0)
                        Elements2.Add(E);
                }
 
                Variables[this.reference.VariableName] = Argument.Encapsulate(Elements2, this);
            }
 
            return Result;
        }
 
    }
}