AppleScript: The Definitive Guide, 2nd Edition

List

A list is a collection corresponding roughly to what many other languages would call an array—it's an ordered set of values. These values are its items. Each item can be of any datatype (including a list). Lists are returned by scriptable applications from element specifiers such as every and boolean tests. They are useful for passing as parameters to commands and handlers because they can contain any number of items. AppleScript provides some operators for testing the contents of a list and for concatenating lists to form a new list (see Chapter 15).

A literal list is delimited by curly braces. Its contents can be literal values, variable names, or any other expressions that AppleScript can evaluate meaningfully; they are separated by commas. The literal empty list is just a pair of curly braces:

set empty to {}
set pep to {"Mannie", "Moe"}
set pep3 to "Jack"
empty & pep & {pep3} -- {"Mannie", "Moe", "Jack"}

You can assign a list of values to a literal list of variable names or other references as a shorthand for performing multiple assignments. The assignments are performed pairwise in order: item 1 to item 1, item 2 to item 2, and so on. If the list of values is too long, the extra values are ignored; if it's too short, there's a runtime error. (See "Assignment and Retrieval" in Chapter 7 and "Assignment of Multiple Attributes" in Chapter 11.) For example:

tell application "Finder" set L to {name of folder 1, name of folder 2} set {oldname1, oldname2} to L set {name of folder ...