The VisualLangLab API documentation now includes a Clojure companion for the existing Java client example.
Unlike other parser-generators, VisualLangLab does not generate any code. Instead, it turns its visually depicted rules (or grammar-trees, see figure below) directly into a parser instance at run-time. These parsers are accessible via the API from programs in any JVM language.
VisualLangLab is the Java world's only parser-generator that supports all JVM languages. An introduction to VisualLangLab can be found in Grammar Without Tears. And a more elaborate tutorial is available in A Quick Tour.