This is the core implementation of the Rascal meta-programming language. It contains the interpreter, the parser generator, the parser run-time, the standard library, the online documentation and the type checker.
Other relevant repositories:
Rascal is used in practice, but we consider it to be alpha software because we are still improving the language.
Please visit http://www.rascal-mpl.org
For questions use the rascal tag on StackOverflow.