PetitParser is a dynamic parser framework combining ideas from scannerless parsing, parser combinators, parsing expression grammars and packrat parsers. In this hands-on session we learn how to build simple parsers and how to model, test, compose and reuse complex grammars. Additionally, we will look at some tools and the reflective facilities provided by the PetitParser framework. Basic knowledge of the Smalltalk programming language is a requirement. Bring your laptop to reproduce the examples and solve some simple tasks.