PATHMac OS 8 and 9 Developer Documentation > Interapplication Communication > AppleScript for Scripters >

AppleScript Language Guide

   

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Kinds of Errors

Every script error falls into one of the following categories:

• Operating system errors are errors that occur when AppleScript or an application requests services from the Mac OS. They are rare, and, more importantly, there's usually nothing you can do about them in a script. A few, such as "File <name> wasn ' t found" and "Application isn ' t running" , make sense for scripts to handle. These errors are listed in Operating System Errors.
• Apple event errors are operating system errors that occur when the underlying message system for AppleScript--known as Apple events--fails. Many of these errors, such as "No user interaction allowed" , are of interest to scripters. Also of interest to users are errors that have to do with reference forms, as well as errors such as "No such object" . These errors are listed in Apple Event Errors.
• An application scripting error is an error returned by an application when handling standard AppleScript commands (commands that apply to all applications). Many of these, such as "The specified object is a property, not an element" , are of interest to users and should be handled. These errors are listed in Application Scripting Errors. Applications can define additional error messages for the AppleScript commands they handle. An application that defines such errors should list them in its documentation.
• AppleScript errors are errors that occur when AppleScript processes script statements. Nearly all of these are of interest to scripters. These errors are listed in AppleScript Errors.
• Script errors are error messages sent by a script using the Error command. Scripts that define additional errors will often include descriptions of the errors in their documentation.