A (Toy) Dependency Injection Framework For Haskell

Done

• some way of wiring up dependencies

To Do

• documentation
• support monadic dependencies (e.g. a component that requires an IORef)
• upload to Hackage
• some way of solving the robot legs problem
  • probably enough to insist that robot leg and foot component types take an extra phantom parameter
• some way of reducing boilerplate
• do something sensible when there are dependency cycles
  • tie the knot when pure (optionally give an error instead? — dependency cycles are arguably bad design)
  • runtime error when impure (except when MonadFix?)
• support polymorphic factories (i.e. the component type is parameterised by a monad, as are its dependencies; we shouldn't have to specify which monad when registering the factory in a module, only when we ask the module for a component) (this might not be possible)