Apple WebObjects 3.5 - Manual (Page 167)

WebScript Language Elements
167
In these declarations, id is a data type. The id type is a reference to any
object—in reality, a pointer to the object’s data (its instance variables). Like
a C function or an array, an object is identified by its address; thus, all
variables declared in WebScript are pointers to objects. In the examples
above,
myVar1 and myVar2 could be any object: a string, an array, or a custom
object from your application.
Note: Unlike C, no pointer manipulation is allowed in WebScript.
Instead of using id , you can specifically refer to the class you want to
instantiate using this syntax:
className * variableName ;
For example, you could specify that a variable is an NSString object using
this syntax:
NSString *myString1;
NSString *myString1, *myString2;
For more information on specifying class names in variable declarations, see
the section “Data Types” (page 174).
In WebScript, there are two basic kinds of variables: local variables and
instance variables. You declare instance variables at the top of the file, and
you declare local variables at the beginning of a method or at the beginning
of a block construct (such as a
while loop). The following shows where
variables can be declared:
id instanceVariable; // An instance variable for this class.
- aMethod {
id localVariable1; // A local variable for this method.
while (1) {
NSString *localVariable2; // A local variable for this block.
}
}
Variables and Scope
Each kind of variable has a different scope and a different lifetime. Local
variables are only visible inside the block of text in which they are declared.
In the example above,
localVariable1 is declared at the top of a method. It is
accessible within the entire body of that method, including the while loop. It
is created upon entry into the method and released upon exit. localVariable2 ,
on the other hand, is declared in the while loop construct. You can only access
it within the curly braces for the while loop, not within the rest of the method.