org.lsmp.djep.xjep

Class MacroFunction

java.lang.Object

org.nfunk.jep.function.PostfixMathCommand

org.lsmp.djep.xjep.MacroFunction

All Implemented Interfaces:

PostfixMathCommandI

public class MacroFunction
extends PostfixMathCommand

A function specified by a string. For example

 XJepI jep = new XJep();
 j.addFunction("zap",new MacroFunction("zap",1,"x*(x-1)/2",j));
 Node node = j.parse("zap(10)");
 System.out.println(j.evaluate(node)); // print 45
 

The names of the variables used inside the function depends on the number of arguments:

• One argument variable must be x: new MacroFunction("sec",1,"1/cos(x)",j)
• Two arguments variables must be x or y: new MacroFunction("myPower",2,"x^y",j)
• Three or more arguments variables must be x1, x2, x3,...: new MacroFunction("add3",3,"x1+x2+x3",j)

Author:

R Morris. Created on 18-Jun-2003

Field Summary

Fields inherited from class org.nfunk.jep.function.PostfixMathCommand

curNumberOfParameters, numberOfParameters

Constructor Summary

Constructors

Constructor and Description
MacroFunction(String inName, int nargs, String expression, XJep jep) Create a function specified by a string.

Method Summary

Modifier and Type	Method and Description
String	getName()
Node	getTopNode()
void	run(Stack stack) Calculates the value of the expression.

Methods inherited from class org.nfunk.jep.function.PostfixMathCommand

checkNumberOfParameters, checkStack, getNumberOfParameters, setCurNumberOfParameters

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MacroFunction

public MacroFunction(String inName,
                     int nargs,
                     String expression,
                     XJep jep)
              throws IllegalArgumentException,
                     ParseException

Create a function specified by a string. For example new MacroFunction("sec",1,"1/cos(x)",tu) creates the function for sec. Variable names must be x,y for 1 or 2 variables or x1,x2,x3,.. for 3 or more variables.

Parameters:

inName - name of function

nargs - number of arguments

expression - a string representing the expression.

jep - a reference to main XJep object.

Throws:

IllegalArgumentException

ParseException

Method Detail

getName

public String getName()

getTopNode

public Node getTopNode()

run

public void run(Stack stack)
         throws ParseException

Calculates the value of the expression.

Specified by:

run in interface PostfixMathCommandI

Overrides:

run in class PostfixMathCommand

Throws:

ParseException - if run.