I am not answering the original question and please excuse it, but you may be interested in our sbt-rats plugin for the sbt tool . He uses Rats! parser generator for Java, but simplifies its use from Scala.
Rats! uses grammars parsing as a syntax description formalism rather than context-free grammars and definitely not LALR (1) grammars. sbt-rats also has a high-level syntax definition language, which in most cases means that you don't need to write semantic actions to get a syntax tree that represents your input. The plugin will additionally generate case classes for representing the tree and a pretty-printer for the tree structure.