Package-level function closures are very useful for creating generalized functionality which does not require a class (static methods) or instance of a class (instance methods).

Unlike static and instance methods package-level function closures are not associated with a class or instance of a class but rather with a package. There are no syntactical differences between package-level functions and static or instance methods.

Package-level functions are for the most part utility functions; for instance the flash.utils package contains a number of package-level functions, the most common of which are describeType(), getDefintionByName(), getTimer() and so forth.

Package-level function closures are created by defining a function directly inside the body of a package (where class and interfaces are defined), as can be seen in the following example:

Calling a package level function is straightforward, simply import the function just as you would a class or interface and then invoke the function directly…

Typically you will find that most functionality can be grouped to a Class or an instance object, however on occasion you may identify specific functionality which is common to packaged functionality as opposed to a specific object, and in these cases utilizing package-level functions is a great option.

This entry was posted on Tuesday, May 6th, 2008 at 5:31 am and is filed under Adobe Flash, Adobe Flex, ActionScript 3, Object Oriented Design, Software Engineering. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.