8.1 Extra arguments

In the previous lecture we only scratched the surface of DCG notation: it actually offers a lot more than we've seen so far. For a start, DCGs allow us to specify extra arguments. Extra arguments can be used for many purposes; we'll examine three.

• 8.1.1 Context free grammars with features

• 8.1.2 Building parse trees

• 8.1.3 Beyond context free languages