Apple WebObjects 3.5 - Manual (Page 171)

WebScript Language Elements
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• A return type of void is not allowed:
// This won’t work either.
- (void) aMethod:(NSString *)anArg { ... }
Both example methods return a value, stored in result . If a method doesn’t
return a meaningful value, you don’t have to include a return statement
(and, as stated above, even if a method returns no value you shouldn’t
declare it as returning
void ).
Invoking Methods
When you want an object to perform one of its methods, you send the
object a message. In WebScript, message expressions are enclosed in square
brackets:
[ receiver message ]
The receiver is an object, and the message tells it what to do. For example, the
following statement tells the object
aString to perform its length method, which
returns the string’s length:
[aString length];
When the method requires arguments, you pass values by placing them to
the right of the colon. For example, to invoke the method
addFirstValue:toSecondValue: shown previously, you would do this:
three = [aComponent addFirstValue:2 toSecondValue:1];
One message can also be nested inside another. Here the description method
returns the string representation of an NSCalendarDate object myDate , which
is then appended to aString . The resulting string is assigned to newString :
newString = [aString stringByAppendingString:[myDate description]];
As another example, here the array anArray returns an object at a specified
index. That object is then sent the description message, which tells the object
to return a string representation of itself, which is assigned to desc :
id desc = [[anArray objectAtIndex:anIndex] description];
Accessor Methods
As stated previously, you can access any instance variable within any
method declared in the same object. If you need to access a variable in a
different object, you must send a message to that object.
Accessor methods are methods that other objects can use to access an object’s
instance variables. When you declare an instance variable, WebScript