Chapter 19. Dictionaries
dictionary is a
application’s way of letting the world know how it
extends AppleScript’s vocabulary. This extended
vocabulary is called the application’s
AppleScript itself defines few commands, and has few abilities of its
own; its value emerges when it is used for communicating, by means of
Apple events, with scriptable applications. A scriptable application
provides powers that AppleScript lacks, along with terminology that
permits the programmer to harness those powers. For example,
AppleScript can’t make a new folder on your hard
drive, but the Finder can; and the Finder supplements
AppleScript’s vocabulary with terms such as
folder so that you can
use AppleScript to command it (the Finder) to do so. This
supplementary terminology is made available through the
A dictionary has two intended audiences:
- The AppleScript programmer
The AppleScript programmer studies a human-readable display of an application’s dictionary to learn what English-like terms beyond those built into the AppleScript language itself may be used when targeting that application.
AppleScript uses an application’s dictionary at compile time to look up the terms that the programmer uses. In this way, AppleScript confirms that the terms really exist; since they don’t exist within AppleScript itself, AppleScript cannot know without a dictionary that the programmer isn’t just talking nonsense. AppleScript also uses the dictionary ...
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