ActionScript for Flash MX: The Definitive Guide, Second Edition

Function Class

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ActionScript Language Reference

Function Class

object-oriented representation of ActionScript functions

Flash 6

Properties

prototype An object specifying methods and properties for a class.

Methods

apply() Invoke a function as an object method, passing parameters in an array.

call() Invoke a function as an object method.

toString() Returns a string representation of the function object.

Description

In ActionScript, every function, both user-defined and built-in, is an instance of the Func-

tion class. As an object, every function can have properties and methods, and every

function can be stored, passed, and compared as ActionScript data. While functions-as-

objects is a foreign (and perhaps strange) concept to some programmers, it is a core

component of the ECMA-262 implementation of object-oriented programming. In Action-

Script, every function has the potential to be used as a class constructor. Hence, every

function defines a

prototype property specifying the methods and properties that will be

inherited by the instances of the class. Furthermore, every function has the potential to be

used as a method. Hence, every function can be stored as an object property (defining it as

a method for that object). These and other uses of functions in ActionScript’s inheritance

system ...