ILE RPG Structure: Subprocedures, Modules and Service Programs
Many RPG programmers are familiar with the concepts and basic rules of coding subprocedures, parameters and return values. But many programmers are puzzled about how to create modules and service programs based on multiple subprocedures.

In this session, Craig describes many "best practices" for constructing modules. You'll see how to design modules that have "worker" subprocedures and "accessor" subprocedures; how to work with optional and default values; techniques to manage and easily reuse source code; a template for designing modules; and rules of thumb for dealing with change after putting modules into production. Once you understand how to construct modules, you're well on your way to creating a library of code that you can easily extend and use as the basis for future development. As an added bonus, learning how to effectively work with modules is great preparation for learning other languages (such as Java) that use similar program construction techniques.