Introduction to AppleScript Language Guide

This document is a guide to the AppleScript language—its lexical conventions, syntax, keywords, and other elements. It is intended primarily for use with AppleScript 2.0 or later and macOS version 10.5 or later.

AppleScript 2.0 can use scripts developed for any version of AppleScript from 1.1 through 1.10.7, any scripting addition created for AppleScript 1.5 or later for macOS, and any scriptable application for Mac OS v7.1 or later. A script created with AppleScript 2.0 can be used by any version of AppleScript back to version 1.1, provided it does not use features of AppleScript, scripting additions, or scriptable applications that are unavailable in that version.

What Is AppleScript?

AppleScript is a scripting language created by Apple. It allows users to directly control scriptable Macintosh applications, as well as parts of macOS itself. You can create scripts—sets of written instructions—to automate repetitive tasks, combine features from multiple scriptable applications, and create complex workflows.

A scriptable application is one that can be controlled by a script. For AppleScript, that means being responsive to interapplication messages, called Apple events, sent when a script command targets the application. (Apple events can also be sent directly from other applications and macOS.)

AppleScript itself provides a very small number of commands, but it provides a framework into which you can plug many task-specific commands—those provided by scriptable applications and scriptable parts of macOS.

Most script samples and script fragments in this guide use scriptable features of the Finder application, scriptable parts of macOS, or scriptable applications distributed with macOS, such as TextEdit (located in /Applications).

Who Should Read This Document?

You should use this document if you write or modify AppleScript scripts, or if you create scriptable applications and need to know how scripts should work.

AppleScript Language Guide assumes you are familiar with the high-level information about AppleScript found in AppleScript Overview.

Organization of This Document

This guide describes the AppleScript language in a series of chapters and appendixes.

The first five chapters introduce components of the language and basic concepts for using it, then provide additional overview on working with script objects and handler routines:

• AppleScript Lexical Conventions describes the characters, symbols, keywords, and other language elements that make up statements in an AppleScript script.

• AppleScript Fundamentals describes basic concepts that underly the terminology and rules covered in the rest of this guide.

• Variables and Properties describes common issues in working with variables and properties, including how to declare them and how AppleScript interprets their scope.

• Script Objects describes how to define, initialize, send commands to, and use inheritance with script objects.

• About Handlers provides information on using handlers (a type of function available in AppleScript) to factor and reuse code.

The following chapters provide reference for the AppleScript Language:

• Class Reference describes the classes AppleScript defines for common objects used in scripts.

• Commands Reference describes the commands that are available to any script.

• Reference Forms describes the syntax for specifying an object or group of objects in an application or other container.

• Operators Reference provides a list of the operators AppleScript supports and the rules for using them, along with sections that provide additional detail for commonly used operators.

• Control Statements Reference describes statements that control when and how other statements are executed. It covers standard conditional statements, as well as statements used in error handling and other operations.

• Handler Reference shows the syntax for defining and calling handlers and describes other statements you use with handlers.

The following chapter describes an AppleScript-related feature of macOS:

• Folder Actions Reference describes how you can write and attach script handlers to specific folders, such that the handlers are invoked when the folders are modified.

The following appendixes provide additional information about the AppleScript language and how to work with errors in scripts:

• AppleScript Keywords lists the keywords of the AppleScript language, provides a brief description for each, and points to related information.

• Error Numbers and Error Messages describes error numbers and error messages you may see in working with AppleScript scripts.

• Working with Errors provides detailed examples of handling errors with try Statements and error Statements.

• Double Angle Brackets describes when you are likely to see double angle brackets (or chevrons—«») in scripts and how you can work with them.

• Libraries using Load Script describes how to save libraries of handlers and access them from other scripts.

• Unsupported Terms lists terms that are no longer supported in AppleScript.