record
A
record value type is close to what a Perl
programmer knows as a hash or associative array and what a Java
programmer would recognize as the HashMap class. This is a powerful
data type that lets you store name/value or property/value pairs in a
variable. These values are then accessible by the property name (not
the item number). For instance:
get name of theRec
from the preceding syntax example returns “AppleScript in a Nutshell.” But:
get item 1 of theRec
raises an error; you just cannot use the latter reference method.
You can find out how many property/value pairs there are in a record
by getting its length property, as in:
length of theRec
(which returns 2). You can change values by referring to the property
name (unless the record is a read-only application
property). You can also add to a record by
concatenating another record to it:
get length of theRec -- returns 2
set subject of theRec to "AppleScript language"
set theRec to theRec & {users:"Mac scripters"}
get theRec (* returns {name:"AppleScript in a Nutshell", subject:"AppleScript
language", users:"Mac scripters"} *)You can coerce a record to a
list type, but the record (now
a list) will lose all of the property names. For
example:
get theRec as list
will return:
{"AppleScript In a Nutshell", "AppleScript language", "Mac scripters"}.Records can have expressions or variables as property values, as in the following example (however, you cannot use variable values for property names):
set myVar to "A variable"
set twoRec to {calc:(2 + 2.5), var:myVar} as record (* returns {calc:4.5,
var:"A variable"} *)
set twoRec to {calc:(2 + 2.5), var:myVar,myVar: 7} as record (* returns
{calc:4.5, var:"A variable",myVar: 7} and doesn't evaluate the myVar variable
at the end of the record*)You cannot use two-word property names when creating your own
record. You will have to use capital letters or
underscore characters to create more descriptive property names:
set climberName to {FirstName: "Edmund", last_name: "Hillary"}.as opposed to:
set climberName to {First Name: "Edmund", Last Name: "Hillary"}.