AppleScript: The Definitive Guide, 2nd Edition

Record

A record is an unordered collection of name-value pairs. Each value may be of any type. Records are passed to a few important commands, such as make, and are returned by scriptable applications and scripting additions as a way of providing a "table" of information (see Chapter 21). They are useful for passing as parameters to handlers because they can contain any number of items. AppleScript provides some operators for testing the contents of a record and for concatenating records to form a new record (see Chapter 15).

A literal record looks like a literal list except that each item has a name. The name is separated from the corresponding value with a colon:

set R to {who:"Matt", town:"Ojai"}

There is no empty record as distinct from the empty list; the empty list is treated as the empty record for purposes of containment and concatenation. A record has no item elements, its items cannot be referred to by index number, and you can't talk about the beginning or end of a record.

You can assign a record of values to a literal record of variable names or other references as a shorthand for performing multiple assignment. The assignments are performed pairwise by name, independently. If the record of values includes names that aren't in the record of variables, the extra values are ignored; if it's missing any names that are in the record of variables, there's a runtime error. See "List," earlier in this chapter. For example:

local who, town set {who:who, town:town} to {town:"Ojai", ...