The RPG Programmer's Guide to RPG IV and ILE

Aimed at the experienced RPG programmer, this book addresses the difference between RPG III and RPG IV so that you can quickly become a productive RPG IV programmer. It contains extensive code examples that compare the two RPG languages and introduces the ILE capabilities that can be used to your advantage. Topics covered include how to use keyword-style H-specs and F-specs, as well as how to use the new D-specs to define tables, arrays, data structures with subfields, standalone fields, and data areas. The authors cover the changes to I-specs and O-specs and explain how you can improve your productivity with the free form EVAL, IF, DOW, and DOU operations. This book also contains an introduction to date, time, and time-stamp data types, as well as date arithmetic. It also shows you how to realize program performance improvements for bound calls. Based on the authors' previous title, ILE RPG for RPG/400 Programmers, this new book provides even more powerful information to quickly help you become productive in RPG IV. All of the new Version 4 capabilities of the RPG IV language and ILE are covered. There are two new chapters on subprocedures: One chapter explains why the powerful new capabilities of subprocedures that let you break modules down into multiple procedures are so important, and another chapter shows you, by example, how to code the P-specs that make it all possible. The chapter on conditional compiler objects shows you how the old directives have been enhanced and what new directives are available. In addition, there is new information on implementing object-oriented (OO) concepts in RPG. With the industry quickly moving toward OO programming, it is crucial that RPGprogrammers keep up to date on this powerful concept and understand how it applies to modern RPG IV constructs. Appendices include utilities and programs that you can add to your copybook and learn from: changing case with RPG IV subprocedures, converting numbers to words, recursive programming, and exception and error codes. Plus, another new appendix features the limit changes for RPG IV defined.