Chapter 13. Datatypes
A
datatype is a classification of a value; every
value is of one datatype or another. This is what AppleScript calls a
class (see Chapter 10). For example,
string is a datatype, integer
is a datatype, and so forth. AppleScript provides a number of native
datatypes; this chapter describes them.
Scriptable applications can extend the language by providing
additional datatypes. For example, the Finder implements a
folder datatype (or class). But such additional
datatypes are confined to the application that defines them; a value
returned by a scriptable application must be either a reference to an
object belonging to that application, or one of
AppleScript’s native datatypes.
Some values can be mutated from one datatype to another. Such a
mutation is called
coercion
. To put it more strictly: for some pairs
of datatype, call them datatype 1 and datatype 2, it is the case that
at least some values of datatype 1 can be coerced to a value of
datatype 2. For example, the string "1" can be
coerced to a number; when that happens, you get the number
1. What coercions are possible, and how they are
performed, is explained in Chapter 14 and
Chapter 15.
Boolean
A boolean is a
datatype consisting of exactly two possible values,
true and false.
class of true -- boolean class of (1 < 2) -- boolean
The main use for a boolean is as a
condition in a control statement, such as a repeat
while block (Chapter 12). For
the operators that generate and combine booleans, see Chapter ...
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.
