RPG Looks into the Future
February 15, 2006 Ted Holt
If you could write a program that could accurately predict the future, you’d be set for life. Unfortunately–or fortunately, depending on your point of view–such a program is not possible. But you can make a program look ahead as it reads a sequential data set, and that can be a valuable asset.
The RPG cycle includes a handy lookahead feature, which allows a program to view data in the next record to be read, but it’s not available for externally described files, nor for full-procedural files. However, rolling your own lookahead logic is easy. To demonstrate just how easy it