MinusOne.cs

using System;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects;
using Waher.Script.Operators.Assignments.Pre;
 
namespace Waher.Script.Operators.Arithmetics
{
    public class MinusOne : UnaryOperator, IDifferentiable
    {
        public MinusOne(ScriptNode Operand, int Start, int Length, Expression Expression)
            : base(Operand, Start, Length, Expression)
        {
        }
 
        public override IElement Evaluate(IElement Operand, Variables Variables)
        {
            if (Operand.AssociatedObjectValue is double DOp)
                return new DoubleNumber(DOp - 1);
            else
                return PreDecrement.Decrement(Operand, this);
        }
 
        public ScriptNode Differentiate(string VariableName, Variables Variables)
        {
            if (this.op is IDifferentiable D)
                return D.Differentiate(VariableName, Variables);
            else
                throw new ScriptRuntimeException("Argument not differentiable.", this);
        }
 
    }
}