Webscript language elements, Variables – Apple WebObjects 3.5 User Manual

Page 166

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Chapter 10

The WebScript Language

166

id number, aName;

- awake {

if (!number) {

number = [[self application] visitorNum];
number++;
[[self application] setVisitorNum:number];

}
return self;

}

- recordMe {

if ([aName length]) {

[[self application] setLastVisitor:aName];
[self setAName:@""]; // clear the text field

}

}

Instance variables are declared at the top of the script file. In the example above,

number

and

aName

are instance variables. An object’s behavior is defined by its

methods.

awake

and

recordMe

are examples of methods.

When you define a new class, you subclass an existing class. Subclassing gives
you access not only to the variables and methods that you explicitly define but
also to the variables and methods defined for the existing class (called the
superclass). As you learned in the chapter “What Is a WebObjects Application?”
(page 17), WebObjects applications can contain three kinds of script files: a
component script inside a

.wo

directory, an application script, and a session script.

These three kinds of scripts create subclasses of the WebObjects classes
WOComponent, WOApplication, and WOSession, respectively. As you’ll learn
later, you can also subclass other classes in WebScript, but doing so is rare.

WebScript Language Elements

This section describes WebScript language elements. WebScript is based on
Objective-C, which in turn is based on C. If you are familiar with C, most of the
statements, operators, and reserved words will be very familiar to you. Because
WebScript is an object-oriented programming language and because all
variables are objects, there is some difference in the way you declare variables
and there is added syntax for working with objects.

Variables

To declare a variable in WebScript, use the syntax:

id myVar;

id myVar1, myVar2;

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