ptolemy.data.expr
Class ExpressionFunction

java.lang.Object
  ptolemy.data.expr.ExpressionFunction

All Implemented Interfaces:

Function

public class ExpressionFunction
extends java.lang.Object
implements Function

An implementation of a function closure that encapsulates an expression tree. Instances of this class are created during the evaluation of function closure expressions in the expression language, like "function(x:int, y:int) x+y".

Since:

Ptolemy II 2.1

Version:

$Id: ExpressionFunction.java 57040 2010-01-27 20:52:32Z cxh $

Author:

Steve Neuendorffer, Xiaojun Liu

See Also:

ASTPtRootNode

Accepted Rating:

Red (neuendor)

Proposed Rating:

Yellow (neuendor)

Field Summary

private java.util.List	_argumentNames
private Type[]	_argumentTypes
private ASTPtRootNode	_exprRoot

Constructor Summary

ExpressionFunction(java.util.List argumentNames, Type[] argumentTypes, ASTPtRootNode exprRoot)
Construct a function closure that encapsulates an expression tree.

Method Summary

Token	apply(Token[] arguments) Apply the function to the list of arguments, which are tokens.
int	getNumberOfArguments() Return the number of arguments of the function.
boolean	isCongruent(Function function) Return true if this function is congruent to the given function.
java.lang.String	toString() Return a string representation of this function.

Methods inherited from class java.lang.Object

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

Field Detail

_exprRoot

private ASTPtRootNode _exprRoot

_argumentNames

private java.util.List _argumentNames

_argumentTypes

private Type[] _argumentTypes

Constructor Detail

ExpressionFunction

public ExpressionFunction(java.util.List argumentNames,
                          Type[] argumentTypes,
                          ASTPtRootNode exprRoot)

Construct a function closure that encapsulates an expression tree.

Parameters:

argumentNames - The names of the arguments.

argumentTypes - The types of the arguments.

exprRoot - The Expression tree that describes the function.

Method Detail

apply

public Token apply(Token[] arguments)
            throws IllegalActionException

Apply the function to the list of arguments, which are tokens.

Specified by:

apply in interface Function

Parameters:

arguments - The list of arguments.

Returns:

The result of applying the function to the given arguments.

Throws:

IllegalActionException - If thrown during evaluating the function.

getNumberOfArguments

public int getNumberOfArguments()

Return the number of arguments of the function.

Specified by:

getNumberOfArguments in interface Function

Returns:

The number of arguments of the function.

isCongruent

public boolean isCongruent(Function function)

Return true if this function is congruent to the given function. Classes should implement this method so that two functions are congruent under any renaming of the bound variables of the function. For simplicity, a function need only be congruent to other functions of the same class.

Specified by:

isCongruent in interface Function

Parameters:

function - The function to check congruency against.

Returns:

True if this function is congruent.

toString

public java.lang.String toString()

Return a string representation of this function.

Specified by:

toString in interface Function

Overrides:

toString in class java.lang.Object

Returns:

A string representation of this function.