-- | This library provides Uniplate-style generic traversals for fixed-point types.
-- The advantages of using fixed-point types instead of explicit recursion are the following:
--
--   * we can add attributes to the nodes of an existing tree;
--
--   * there is no need for a custom type class, we can build everything on the top of
--     @Functor@, @Foldable@ and @Traversable@, for which GHC can derive the instances for us;
--
--   * some operations can retain the structure of the tree, instead flattening
--     it into a list;
--
--   * it is quite straightforward to provide a generic zipper.
--
-- The main disadvantage is that it does not work well for
-- mutually recursive data types, and that pattern matching becomes
-- more tedious (but there are partial solutions for the latter).
--
-- Consider as an example the following simple expression language,
-- encoded by a recursive algebraic data type:
--
-- > Expr 
-- >   = Kst Int 
-- >   | Var String 
-- >   | Add Expr Expr
-- >   deriving (Eq,Show)
--
-- We can open up the recursion, and obtain a /functor/ instead:
--
-- > Expr1 e 
-- >   = Kst Int 
-- >   | Var String 
-- >   | Add e e 
-- >   deriving (Eq,Show,Functor,Foldable,Traversable)
--
-- The fixed-point type 'Mu'@ Expr1@ is isomorphic to @Expr@.
-- However, we can also add some attributes to the nodes:
-- The type 'Attr' @Expr1 a = @'Mu'@ (@'Ann'@ Expr1 a)@ is the type of
-- with the same structure, but with each node having an extra
-- field of type @a@.
--
-- The functions in this library work on types like that: 'Mu'@ f@,
-- where @f@ is a functor, and sometimes explicitely on 'Attr'@ f a@.
-- 
-- This module re-exports most of the functionality present in the library.
--
-- The library should be fully Haskell98 compatible, with the exception
-- of the module "Data.Generics.Fixplate.Structure", which needs
-- the @Rank2Types@ extension. For compatibility, the functionality
-- of this module is at the moment only provided when compiled with GHC or Hugs.
--
module Data.Generics.Fixplate 
  ( module Data.Generics.Fixplate.Base
  , module Data.Generics.Fixplate.Traversals
  , module Data.Generics.Fixplate.Morphisms
  , module Data.Generics.Fixplate.Attributes
--  , module Data.Generics.Fixplate.Zipper
  , module Data.Generics.Fixplate.Structure
  , Functor(..) , Foldable(..) , Traversable(..)
  )
  where
  
--------------------------------------------------------------------------------
  
import Data.Generics.Fixplate.Base
import Data.Generics.Fixplate.Traversals
import Data.Generics.Fixplate.Morphisms
import Data.Generics.Fixplate.Attributes
-- import Data.Generics.Fixplate.Zipper
import Data.Generics.Fixplate.Structure  

import Data.Foldable
import Data.Traversable

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