Apple WebObjects 3.5 - Manual (Page 172)

Chapter 10 The WebScript Language
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automatically defines two accessor methods: one to retrieve the instance
variable’s value, and one to change the value.
For example, the Application.wos script in the Visitors example declares this
instance variable, which keeps track of the number of visitors:
id visitorNum;
When WebScript parses this file, it sees this declaration and implicitly defines
two methods that work like this:
- visitorNum {
return visitorNum;
}
- setVisitorNum:newValue {
visitorNum = newValue;
}
(You don’t see these methods in the script file.) The Main.wos script access the
application’s visitorNum variable using these statements:
number = [[self application] visitorNum];
...
[[self application] setVisitorNum:number];
Note: self is a keyword that represents the current object. For more information,
see “Reserved Words” (page 178).
You can also access an instance variable declared in one component script from
another component script. This is something you commonly do right before you
navigate to a new page, for example:
id anotherPage = [[self application] pageWithName:@"Hello"];
[anotherPage setNameString:newValue];
The current script uses the statement
[anotherPage setNameString:newValue];
to set the value of nameString , which is declared in the page named Hello.
Sending a Message to a Class
Usually, the object receiving a message is an instance of a class. For example, in
this statement the variable
aString is an instance of the class NSString:
[aString length];
You can also send messages to a class. You send a class a message when you want
to create a new instance of that class. For example this statement tells the class
NSString to invoke its
stringWithString: method, which returns an instance
of NSString that contains the specified string: