AppleScript in a Nutshell

Name

open handler

Syntax

on open(list_of_aliases)
   set item1 to the first item of list_of_aliases as string
   display dialog "Here's the path of the first object you dragged over¬ 
   me: " & item1
end open

Description

An open Apple event is sent to any Mac application when you drag file, folder, or disk icons on to its own icon in the Finder. If an icon is not highlighted when you drag the object over it, then the application or other object associated with that icon is not designed to handle these drag-and-drop events. If you drag files and other icons over an AppleScript applet, the applet receives an open command that triggers any open handlers that are defined in that applet. They look like this:

on open(list_of_aliases)...end open

The open handler has one parameter—a list type containing alias objects for all the items that were dragged to the applet. If the user only drops one item on the applet icon, then the open subroutine’s parameter will contain a list with one item in it. You can code the open handler to take purposeful actions with files and folders that are dropped on the applet in any way you see fit. Example 2-1 in Chapter 2 shows a script that displays the file type and creator type of any valid object that is dropped on the applet.

Tip

If the applet does not have an open handler or has an empty open handler, then the applet does not take any actions when you drop an object on it; it just opens then quits simultaneously.