use  {Class ('*' | ('/' Global ...)} [, ...]
 alter  {Class ('*' | ('/' Global ...)} [, ...]

Use and Alter declarations list Class Globals accessed within a procedure. A Use declaration provides read-only access while Alter allows you to modify the Global as well. These declarations can take one of the following forms:

Class*                Reference all Globals in a Class.

Class                 Explicitly reference a Global whose name is the same as the Class.

Class/ Global ...     Explicitly reference One or more Globals in a Class

Initially Globals in the Class that contains a procedure will be automatically brought in as a Use (read-only) declaration. For write access you will have to explicitly list it on an Alter declaration. Subsequent Use and Alter declarations are processed by reading the preambles in the Classes in the order listed. There are four kinds of name conflicts that may occur when accessing Globals.

• A Local variable with the same name as an explicitly listed Global will cause a compilation error. If instead the Global is brought in using the "Class*" notation it will be discarded and the Local variable will be used.


• If any two Globals with the same name are explicitly listed on a Use or Alter declaration, a compilation error will be issued.


• If a Global is accessed using the Class* format, a variable with the same name that is explicitly listed will dominate. This will not cause a compilation error.


• If two Globals brought in with the Class* notation with the same name then the one defined first will dominate. In this case the order that modules are listed on the Use or Alter declaration is significant. To clarify this kind of conflict explicitly list the preferred variable.