Properties and Elements
Two
objects may stand in a relationship where one is an
attribute
of the other. It is this relationship of
attribution that is specified by the chain of of
s
and tell
s. Attributes are defined in terms of
classes. (The term
“attribute” is of my own devising,
because the official AppleScript documentation lacks any
comprehensive term for “property or
element.”)
For example, a list has a length
attribute and an
item
attribute—these are facts about any
list because they are facts about the
list
class. That is what makes
this code legal:
set L to {"Mannie", "Moe", "Jack"} length of L -- 3 item 1 of L -- "Mannie"
Recall this code from Chapter 3:
tell application "FrameMaker 7.0" tell document "extra:applescriptBook:ch02places.fm" tell anchored frame 43 get inset file of inset 1 end tell end tell end tell
That code works because, in FrameMaker, the
application
has a document
attribute, a document
has an anchored frame
attribute, an anchored frame
has
an inset
attribute, and an
inset
has an inset file
attribute. As we saw in Chapter 3, working out the
chain of attributes so as to refer successfully to a desired object
is a major part of working with AppleScript. An
application’s dictionary is supposed to help you
with this, though it often falls short (Chapter 19). AppleScript’s own
dictionary is not typically visible, so this book describes the
attributes of the built-in datatypes (Chapter 13).
An attribute is either a property or an element. A property is an attribute ...
Get AppleScript: The Definitive Guide now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.