AppleScript: The Definitive Guide, 2nd Edition

Modes of Scriptability

An application is scriptable if it defines a repertory of Apple events to which it is prepared to respond and publishes that repertory as a dictionary. The dictionary should contain terms that expose the application's core functionality (that caveat is intended to handle the case of applications that publish a dictionary but are not in fact scriptable in any meaningful way; see "Is This Application Scriptable?" in Chapter 1).

There are two additional modes (or levels, or aspects) whereby an application can be scriptable:

Recordable

An application is recordable if it can generate AppleScript code when the user performs ordinary actions in its graphical user interface. This ability can be useful for helping the programmer learn to script the application. There is no way to find out whether and to what extent an application is recordable, other than by trying to record it.

Attachable

The term attachable is somewhat ambiguously defined. Strictly, an attachable application is one that allows the user to customize, by means of a script, what happens when the application receives an Apple event. But it may also be said that an application that allows the user to customize any of its event responses through a script is attachable.

Recordability

As an example of a recordable application, let's take BBEdit. In a script editor application such as Script Editor or Script Debugger, make a new script window, and choose Script → Record (or press the Record button). In ...