PushFirst.cs

using System.Collections.Generic;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
 
namespace Waher.Script.Functions.Vectors
{
    public class PushFirst : FunctionMultiVariate
    {
        private readonly VariableReference reference;
 
        public PushFirst(ScriptNode Element, ScriptNode Vector, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { Element, Vector }, new ArgumentType[] { ArgumentType.Normal, ArgumentType.Vector }, 
            Start, Length, Expression)
        {
            this.reference = Vector as VariableReference;
        }
 
        public override string FunctionName => nameof(PushFirst);
 
        public override string[] DefaultArgumentNames => new string[] { "x", "v" };
 
        public override IElement Evaluate(IElement[] Arguments, Variables Variables)
        {
            if (!(Arguments[1] is IVector V))
                throw new ScriptRuntimeException("Expected second argument to be a vector.", this);
 
            LinkedList<IElement> Elements = new LinkedList<IElement>();
 
            Elements.AddLast(Arguments[0]);
 
            foreach (IElement E in V.VectorElements)
                Elements.AddLast(E);
 
            IElement Result = V.Encapsulate(Elements, this);
 
            if (!(this.reference is null))
                Variables[this.reference.VariableName] = Result;
 
            return Result;
        }
 
    }
}