rockit

Rockit is a potent parser generator and gives you AST's (Abstract Syntax Tree's) which you can pattern match and pretty-print. Rockit does not distinghuish between lexing and parsing so the generated parsers are scanner-/lexer-less. The vision is to extend Rockit with more advanced compiler-related abilities including back-ends and code generation. However, currently the focus is on parsing and AST-related tasks such as transformation.