Constants and Predefined Variables

Constants are reserved words that AppleScript has given a predefined value that you cannot change. There are boolean constants (true or false), date constants (e.g., April, May), and considering or ignoring constants (e.g., case, white space), among others. Predefined variables, on the other hand, have a changeable value. In other words, you can use code such as set pi to 5 and the pi predefined variable will no longer have the value of about 3.14159 in your script! You cannot change the value of the boolean constant false, however (set false to 3 will not compile). The constants are listed in Table 6-1, and the Predefined Variables are listed in Table 6-2. Certain date and time values (i.e., minutes, hours, days, weeks) are changeable in a script like predefined values; however, they are grouped with other date constants for convenience.

Table 6-1. AppleScript Constants

all caps	all lowercase
application responses	ask
bold	case
condensed	current application
date and time constants (e.g., January, February)	diacriticals
expanded	expansion
false	hidden
hyphens	italic
no	outline
plain	punctuation
shadow	small caps
strikethrough	subscript
superscript	true
underline	white space
yes

Table 6-2. AppleScript Predefined Variables

anything	it
me	missing value
pi	result
return	space
tab	version
my