Lady Deirdre is a framework for incremental programming language compilers, interpreters, and source code analyzers.
This framework helps you develop a hybrid program that acts as a language compiler or interpreter and as a language server for a code editor's language extension. It offers the necessary components to create an in-memory representation of language files, including the source code, their lexis and syntax, and the semantic model of the entire codebase. These components are specifically designed to keep the in-memory representation in sync with file changes as the codebase continuously evolves in real time.
Well, the bad news is that its license bites. The good news is that PLT Redex exists and has a much better license along with better formal tooling and presentation.