Roland Muhlberger

Sometimes it simply doesn't matter whether you use a function or an event, just pick one and stick to it This article will shed some light on the differences between the two ways of implementing scripts in PowerBuilder: functions and events. I will discuss the issues in detail, giving background information on each of them. Then you'll be able to decide for yourself when to use which. In the old days of PowerBuilder, functions and events were a different kind of beast. But as PowerBuilder evolved, functions and events became more and more similar. Now many programmers aren't sure what the differences are, and when to use which. In the Sybase PowerBuilder newsgroups (see news://forums.sybase.com) you'll find a wealth of information, but I didn't find a thorough and up-to-date posting on the issue. So in this article I will tell you the similarities and the differenc... (more)

10 PowerBuilder Pitfalls

First the good news: PowerBuilder is a great tool; in fact you can't accidentally do much wrong. This strength is based on a number of reasons. The following is list of why I think PowerBuilder is so great, but you might like to add one or two more items to it: PowerScript is simple; it's easy to learn because of its clearly laid out grammar. PowerScript is a strongly typed language; many problems simply don't arise because of the compiler telling you about an error. PowerScript is easy to read. PowerBuilder itself takes care of the tedious task of correct indentation. Thus Powe... (more)

Using Interfaces with PowerBuilder

Interfaces are one of the most important concepts that have found their way into modern software engineering in the past couple of years. Java, COM, CORBA, C# - all those languages/concepts support interfaces. PowerBuilder does not. This article shows you how to sneak the interface concept into PB by using some of its special features. So Many Interfaces - What This Article Is Not About The term interface is a common one in software engineering. In this article, I define interface to mean "named collection of method definitions." We especially don't deal with: The PBNI, the PowerB... (more)

Using Interfaces with PowerBuilder Part 2 of 2

Wouldn't it be nice if we could use DataWindows, DataStores, and DataWindowChild objects in the same way? This article shows you how. In Part 1 (PBDJ, Vol. 9, issue 11) I described a way to implement Java's and C#'s interface concept into PB. We did the following: Created a wrapper class (the "interface") that has a reference to a PowerObject as an instance variable Created a method within the wrapper class for every method of the interface Called the actual method per dynamic call Encapsulated the call with a TRY/CATCH-block in PB 8 and above At runtime, created the interface o... (more)

Evolution of the Constants

PowerBuilder comes with a wide range of enumerated data types, and the values are easily distinguished by the exclamation mark at the end. However, there is no way to build your own enumerated data type in PowerScript, and it seems that even PB 10 won't help us that much here. (Keep your fingers crossed that user-defined enumerateds will be a part of PB 11.) This article shows how to build a self-describing and robust enumerated data type and discusses the ideas behind it. Stage 0: Using Numbers From the beginning PowerBuilder programmers used numbers to code states in their pr... (more)