First.cs

using Waher.Script.Abstraction.Elements;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Script.Functions.Vectors
{
    public class First : FunctionOneVectorVariable
    {
        public First(ScriptNode Argument, int Start, int Length, Expression Expression)
            : base(Argument, Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(First);
 
        protected override IElement EvaluateNonVector(IElement Argument, Variables Variables)
        {
            return Argument;
        }
 
        public override IElement EvaluateVector(IVector Argument, Variables Variables)
        {
            int c = Argument.Dimension;
            if (c == 0)
                return ObjectValue.Null;
            else
                return Argument.GetElement(0);
        }
 
    }
}