I thought this might be of interest to LtU readers:
Nitra is a language for describing grammars, and the abstract syntax trees to represent them. It is also a build tool to compile the grammars into parsers, and generate the classes required to represent and navigate the AST. And it’s also a set of language services that use the grammar to provide automatic syntax highlighting, outlining and brace matching.
What’s more, Nitra’s grammars are designed to be extensible and reusable. A simple example would be the base building block grammars that ship with Nitra, such as Whitespaces and CStyleComments. Both clearly useful in many languages, and can be simply included and reused in a larger grammar.
The announcement is here. It's available in GitHub and was released under a simplified BSD license.