Editing AppleScript (section)

===Types and objects===
A script can define custom data types, or use one of the many built-in classes and objects which are provided by the language and tend to be recognized by scriptable applications. Notable built-in types and objects include:
; Basic objects
* '''application''': used mostly as a specifier for tell statements (<code>tell application "Finder" …</code>)
* '''script''': script objects are containers for scripts; every AppleScript creates a script object when run, and script objects may be created within AppleScripts
* '''class''': meta-object that specifies the type of other objects
* '''reference''': object that encapsulates an unevaluated object specifier that may or may not point to a valid object; can be evaluated on-demand by accessing its <code>contents</code> property
; Standard data objects
* '''constant''': [[Constant (computer programming)|constant]] value; language-defined constants include <code>pi</code>, <code>tab</code> and <code>linefeed</code>
* '''boolean''': [[Boolean data type|Boolean]] (true/false) value; [[Subclass (computer science)|subclass]] of <code>constant</code>
* '''number''': [[Abstract type|abstract]] [[Superclass (computer science)|superclass]] of <code>integer</code> and <code>real</code>; rarely used directly
* '''integer''': [[Integer (computer science)|integer]]; can be manipulated with built-in mathematical operators
* '''real''': [[floating-point]] ([[Real number|real]]) number; can be manipulated with built-in mathematical operators
* '''date''': date and time
* '''text''': before AppleScript 2.0 (Mac OS X 10.4 and below) the <code>text</code> class was distinct from <code>string</code> and <code>Unicode text</code>, and the three behaved somewhat differently; in 2.0 (10.5) and later, they are all synonyms and all text is handled as [[UTF-16]]<ref name="as-rn-leopard">{{cite web |url=https://developer.apple.com/mac/library/releasenotes/AppleScript/RN-AppleScript/RN-10_5/RN-10_5.html |title=AppleScript Release Notes: 10.5 Changes |website=developer.apple.com |access-date=May 8, 2017}}</ref>
; Containers
* '''list''': ordered list of objects; can contain any class, including other lists and classes defined by applications
* '''record''': keyed list of objects; like a list, except structured as [[key–value pair]]s; runtime keyed access is unsupported; all keys must be compile-time constant identifiers
; File system
* '''alias''': reference to an existing file system object (file or folder); maintains link to file system object if moved or renamed
* '''file''': reference to a file system object; can can refer to an object that does not exist
* '''POSIX file''': reference to a file system object, in plain text, using Unix ([[POSIX]])-style slash (/) notation; not a true data type, as AppleScript automatically converts a POSIX file to an ordinary file<ref>{{cite web|title=POSIX file — Class Reference — AppleScript Language Guide|url=https://developer.apple.com/library/content/documentation/AppleScript/Conceptual/AppleScriptLangGuide/reference/ASLR_classes.html#//apple_ref/doc/uid/TP40000983-CH1g-SW15|website=developer.apple.com|access-date=January 8, 2018|language=en}}</ref>
; Miscellaneous
* '''RGB color''': specifies an RGB triplet (in [[High color#16-bit high color|16-bit high color]] format), for use in commands and objects that work with colors
* '''unit types''': converts between standard units; for instance, a value can be defined as <code>square yards</code>, then converted to <code>square feet</code> by casting between unit types using the <code>as</code> operator