Language Guide

CHAPTER 5
Objects and References
Reference Forms 131
additional guarantees, such as ensuring the uniqueness of an ID among
all objects.
The value of an ID property is not modifiable. It does not change even if the
object is moved within the container. This allows you to save an object’s ID and
use it to refer to the object for as long as the object exists.
Applications are not required to support ID properties. To find out if or how an
application uses ID properties, see the documentation for the application.
Index 5
The Index reference form specifies an object or a location by describing its
position with respect to the beginning or end of a container.
SYNTAX
className [ index ] integer
integer(st | nd | rd | th ) className
( first | second | third | fourth | fifth | sixth |
seventh | eighth | ninth | tenth ) className
( last | front | back ) className
where
className is the class identifier of the object being specified.
integer is an integer that describes the position of the object in relation to the
beginning of the container (if integer is a positive integer) or the end of the
container (if integer is a negative integer).
The forms first, second, and so on are equivalent to the corresponding
integer forms (for example, second word is equivalent to word 2). For
objects whose index is greater than 10, you can use the forms 12th, 23rd,
101st, etc. (Note that any integer followed by any of the suffixes listed is
valid; for example, you can use 11rd to refer to the eleventh object.)