Module project_structure 

Project Structure

Module Dependency Graph

graph TD
    fp-macros["fp-macros<br/>(proc macro crate)"]
    kinds["kinds<br/>Kind + InferableBrand traits"]
    brands["brands<br/>Brand marker types"]
    classes["classes<br/>Type class traits"]
    dispatch["dispatch<br/>Val/Ref routing"]
    functions["functions<br/>Inference wrappers"]
    types["types<br/>Concrete implementations"]

    fp-macros -.->|"used by all modules"| kinds
    kinds --> brands
    kinds --> classes
    classes --> dispatch
    kinds --> dispatch
    classes --> types
    kinds --> types
    brands --> types
    dispatch --> functions
    kinds --> functions

Solid arrows show intra-crate use dependencies. The dashed arrow shows the proc macro crate boundary (fp-macros is a separate crate used at compile time by all fp-library modules).

Modules

• fp-macros: Procedural macros for HKT traits (trait_kind!, impl_kind!, Apply!), do-notation (m_do!, a_do!), brand inference (InferableBrand!), and documentation generation (#[document_module], #[document_signature], etc.).
• kinds: Kind and InferableBrand trait definitions generated by trait_kind!. Provides type application machinery mapping brands to concrete types and back.
• brands: Zero-sized brand marker types (e.g., OptionBrand, VecBrand) that represent unapplied type constructors. Leaf nodes in the dependency graph with no outgoing edges.
• classes: Type class trait definitions (Functor, Monad, Foldable, etc.) and their by-reference counterparts (RefFunctor, RefSemimonad, etc.). Each trait module also defines free function wrappers used by the explicit sub-module.
• dispatch: Val/Ref dispatch traits, inference wrapper functions, and explicit dispatch functions. Each module (e.g., dispatch/functor.rs) contains the dispatch trait with Val/Ref impls, the inference wrapper that combines brand inference (via InferableBrand) with dispatch, and a mod explicit submodule with the brand-explicit variant.
• functions: Facade module (functions.rs) that re-exports inference wrappers from dispatch/ as bare names (map, bind, etc.) and explicit variants in the explicit sub-module. No source files in functions/.
• types: Concrete type implementations of type classes. Contains both custom types (Identity, Lazy, CatList, Coyoneda) and implementations for standard library types (Option, Vec, Result).