using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using SingularSys.Jep;
using SingularSys.Jep.Functions;
using SingularSys.Jep.Types;

namespace HalfTest
{
    public class Half : PostfixMathCommand
    {
        // Constructor sets the number of required parameters for half
        public Half() 
        {
            numberOfParameters = 1;
        }

        public override void Run(Stack<object> inStack)
        {
            // check the stack
            CheckStack(inStack);
            
            // get the parameter from the stack
            Object param = inStack.Pop();
            
            // check whether the argument is of the right type
            if (param is JepDouble) {
                // calculate the result
                double r = ((JepDouble)param).DoubleValue / 2;
                // push the result on the inStack
                inStack.Push(new JepDouble(r));
            } else {
                throw new EvaluationException("Invalid parameter type");
            }
        }
    }
}