Integrated Language Facility (ILF)
As a part of APPX’s application design component, the Integrated Language Facility (ILF) allows you to develop procedural routines within an application. Each ILF routine consists of one or more statements. APPX’s language includes many statement keywords that allow you to perform a wide variety of functions. ILF routines provide you with three primary capabilities:
Explicit control over certain operations, such as file opening and closing. Based on the information you have specified in the data dictionary, APPX provides automatic control of many operations. In some instances, however, you may choose to override a standard operation by defining and executing an ILF routine.
Advanced file processing that provides you with precise control over record access, selection, and update. For example, you can perform complex cross-file updating.
More complex processing functions than the specification method supports. An application may require a complex logic operation in which a number of conditions must be checked before a certain action occurs. For example, you may want to specify that for out-of-state customers only, if their outstanding balance exceeds their credit limit by more than $1,000, a warning message is to be issued. The ILF supports such sophisticated logic and truth table operations.
The Integrated Language Facility is explored in depth in Chapter 4-1: ILF Integration.