Barrier slicing and chopping

One of the critiques on program slicing is that slices presented to the user are hard to understand. This is partly due to bad user interfaces, but mainly related to the problem that slicing ´dumps´ the results onto the user without any explanation. We present an approach that can be used to ´filter´ slices. This approach basically introduces ´barriers´ which are not allowed to be passed during slice computation. An earlier filtering approach is chopping which is also extended to obey such a barrier. The barrier variants of slicing and chopping provide filtering possibilities for smaller slices and better comprehensibility.