PreIncrement.cs

using Waher.Runtime.Collections;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Script.Operators.Assignments.Pre
{
    public class PreIncrement : ScriptLeafNodeVariableReference
    {
        public PreIncrement(string VariableName, int Start, int Length, Expression Expression)
            : base(VariableName, Start, Length, Expression)
        {
        }
 
        public override IElement Evaluate(Variables Variables)
        {
            if (!Variables.TryGetVariable(this.variableName, out Variable v))
                throw new VariableNotFoundScriptException(this.variableName, this);
 
            IElement Value = v.ValueElement;
 
            if (Value.AssociatedObjectValue is double d)
                Value = new DoubleNumber(d + 1);
            else
                Value = Increment(Value, this);
 
            Variables[this.variableName] = Value;
 
            return Value;
        }
 
        public static IElement Increment(IElement Value, ScriptNode Node)
        {
            if (Value is ICommutativeRingWithIdentityElement e)
                return Operators.Arithmetics.Add.EvaluateAddition(Value, e.One, Node);
            else if (Value.IsScalar)
                throw new ScriptRuntimeException("Unable to increment variable.", Node);
            else
            {
                ChunkedList<IElement> Elements = new ChunkedList<IElement>();
 
                foreach (IElement Element in Value.ChildElements)
                    Elements.Add(Increment(Element, Node));
 
                return Value.Encapsulate(Elements, Node);
            }
        }
 
    }
}