Inside Macintosh: AppleScript Language Guide / Part 2 - AppleScript Language Reference

Chapter 3 - Values

Value Class Definitions

This section describes the AppleScript value classes. Table 3-1 summarizes the class identifiers recognized by AppleScript.

AppleScript value class identifiers

Value class identifier	Description of corresponding value
Boolean	A logical truth value
Class	A class identifier
Constant	A reserved word defined by an application or AppleScript
Data	Raw data that cannot be represented in AppleScript, but can be stored in a variable
Date	A string that specifies a day of the week, day of the month, month, year, and time
Integer	A positive or negative number without a fractional part
List	An ordered collection of values
Number	Synonym for class Integer or class Real; a positive or negative number that can be either of class Integer or of class Real
Real	A positive or negative number that can have a fractional part
Record	A collection of properties
Reference	A reference to an object
String	An ordered series of characters
Styled Text	Synonym for a special string that includes style and font information
Text	Synonym for class string

Three identifiers in Table 3-1 act only as synonyms for other value classes: Number is a synonym for either Integer or Real, Text is a synonym for String, and Styled Text is a synonym for a string that contains style and font information. You can coerce values using these synonyms, but the class of the resulting value is always the true value class.

For example, you can use the class identifier Text to coerce a date to a string:

set x to date "May 14, 1993" as text
class of x
--result: string

Although definitions for value class synonyms are included in the sections that follow, they do not correspond to separate value classes. For more information about coercing values using synonyms, see "Coercing Values," which begins on page 66.

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