Package com.singularsys.jep.misc

Class MacroFunction

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.jep.misc.MacroFunction

All Implemented Interfaces:

JepComponent, PostfixMathCommandI, Serializable

public class MacroFunction
extends PostfixMathCommand
implements JepComponent

A function specified by a string. For example

 MacroFunction fact = new MacroFunction(
            "fact",new String[]{"x"}, 
            "if(x>1,x*fact(x-1),1)");
 jep.addFunction("fact",fact);
 fact.init(jep);
 Node n = jep.parse("fact(5)");
 

Author:

R Morris.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected Evaluator	ev
protected final String	expression
protected final int	nParam
protected final Node	preCompiled
protected Node	topNode
protected final String[]	varNames
protected Variable[]	vars

Fields inherited from class com.singularsys.jep.functions.PostfixMathCommand

curNumberOfParameters, name, NaN, numberOfParameters

Constructor Summary

Constructors

Constructor	Description
MacroFunction(Jep jep, String funName, String[] parameters, String expression)	Create a macro function with two or more arguments defined by an expression.
MacroFunction(Jep jep, String funName, String parameter, String expression)	Create a macro function with a single arguments defined by an expression.
MacroFunction(String funName, String[] parameters, String expression)	Create a macro function with two or more arguments defined by an expression.
MacroFunction(String funName, String[] parameters, String expression, Node root)	Create a MacroFunction with a node tree.

Method Summary

Modifier and Type	Method	Description
JepComponent	getLightWeightInstance()	Returns a new copy of the function, uses the MacroFunction(String, String[], String, Node) constructor.
String[]	getParameterNames()
Node	getTopNode()
Variable[]	getVars()	Get the internal variables used, these have specific names like 'fun::x'
void	init(Jep j)	The init method must be called after construction.
void	run(Stack<Object> stack)	Calculates the value of the expression.
String	toString()

Methods inherited from class com.singularsys.jep.functions.PostfixMathCommand

asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, checkNumberOfParameters, getName, getNumberOfParameters, setCurNumberOfParameters, setName, toString

Methods inherited from class java.lang.Object

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

Field Details

nParam

protected final int nParam

varNames

protected final String[] varNames

expression

protected final String expression

preCompiled

protected final Node preCompiled

topNode

protected transient Node topNode

ev

protected transient Evaluator ev

vars

protected transient Variable[] vars

Constructor Details

MacroFunction

public MacroFunction(Jep jep,
 String funName,
 String[] parameters,
 String expression)

Create a macro function with two or more arguments defined by an expression.

Parameters:

jep - The jep instance

funName - name of the function

parameters - an array of the formal parameter names used by the function

expression -

Since:

3.4.0

MacroFunction

public MacroFunction(Jep jep,
 String funName,
 String parameter,
 String expression)

Create a macro function with a single arguments defined by an expression.

Parameters:

jep - The jep instance

funName - name of the function

parameter - the name of the formal parameter.

expression -

Since:

3.4.0

MacroFunction

public MacroFunction(String funName,
 String[] parameters,
 String expression)

Create a macro function with two or more arguments defined by an expression. Use this method for recursive functions like factorial. The init(Jep) method must be called after the function is added to the function table, which will recompile the function.

Parameters:

funName - name of the function

parameters - an array of the formal parameter names used by the function

expression -

MacroFunction

public MacroFunction(String funName,
 String[] parameters,
 String expression,
 Node root)

Create a MacroFunction with a node tree. The ImportationVisitor is used to convert the tree into context for this object.

Parameters:

funName - function name

parameters - list of parameters

expression - string representation of equation

root - root of expressions tree.

Since:

4.0

Method Details

init

public void init(Jep j)

The init method must be called after construction.

Specified by:

init in interface JepComponent

Parameters:

j - jep instance

Throws:

RuntimeException - if errors compiling the expression.

run

public void run(Stack<Object> stack)
         throws EvaluationException

Calculates the value of the expression.

Specified by:

run in interface PostfixMathCommandI

Overrides:

run in class PostfixMathCommand

Parameters:

stack - arguments for function

Throws:

EvaluationException - if the calculation cannot be performed

getTopNode

public Node getTopNode()

getParameterNames

public String[] getParameterNames()

getVars

public Variable[] getVars()

Get the internal variables used, these have specific names like 'fun::x'

Returns:

list of variables

toString

public String toString()

Overrides:

toString in class PostfixMathCommand

getLightWeightInstance

public JepComponent getLightWeightInstance()

Returns a new copy of the function, uses the MacroFunction(String, String[], String, Node) constructor.

Specified by:

getLightWeightInstance in interface JepComponent

Returns:

either a new instance, null or 'this'.