/*****************************************************************************

Exp function

created by R. Morris

JEP - Java Math Expression Parser 2.24
      December 30 2002
      (c) Copyright 2002, Nathan Funk
      See LICENSE.txt for license information.

*****************************************************************************/

package org.nfunk.jep.function;

import java.lang.Math;
import java.util.*;
import org.nfunk.jep.*;
import org.nfunk.jep.type.*;
import org.nfunk.jep.function.PostfixMathCommand;

/**
 * The exp function.
 * Defines a method exp(Object param)
 * which calculates 
 * @author Rich Morris
 * Created on 20-Jun-2003
 */
public class Exp extends PostfixMathCommand
{
	public Exp()
	{
		numberOfParameters = 1;
	}
	
	public void run(Stack inStack)
		throws ParseException 
	{
		checkStack(inStack);// check the stack
		Object param = inStack.pop();
                param = Utility.convertParamToNumber(param);
		inStack.push(exp(param));//push the result on the inStack
		return;
	}

	public Object exp(Object param)
		throws ParseException
	{
		if (param instanceof Complex)
		{
		  	Complex z = (Complex) param;
		  	double x = z.re();
		  	double y = z.im();
		  	double mod = Math.exp(x);
			return new Complex(mod*Math.cos(y),mod*Math.sin(y));
		}
		else if (param instanceof Number) 
		{
			return new Double(Math.exp(((Number)param).doubleValue()));
		}

		throw new ParseException("Invalid parameter type");
	}
}
