Abstract (emphasis added):
This paper introduces TypeLoom, a tool utilising a novel approach to add gradual, optional typing into legacy code bases of dynamically typed languages. TypeLoom leverages the Language Server Protocol (LSP) to provide in-editor type information through inlay hints and collect subsequent through code actions to type information. This approach differs from the ones that exist in so far as it requires no syntactical changes to add type hints (like in Python, TypeScript) and it does not require syntactically correct comments to provide type information (like in @ts-docs and Ruby). TypeLoom utilises a graph based data structure to provide type inference and type checking. This graph-based approach is particularly effective for gradual typing as it allows flexible representation of type relationships and dependencies.