{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances #-}
{-# OPTIONS_GHC -Wno-orphans #-}

{- |
    This module supplies a method for writing 'Uniplate' and 'Biplate' instances.
    This moulde gives the highest performance, but requires many instance definitions. The
    instances can be generated using Derive: <http://community.haskell.org/~ndm/derive/>.

    To take an example:

    > data Expr = Var Int | Pos Expr String | Neg Expr | Add Expr Expr
    > data Stmt = Seq [Stmt] | Sel [Expr] | Let String Expr
    >
    > instance Uniplate Expr where
    >     uniplate (Var x  ) = plate Var |- x
    >     uniplate (Pos x y) = plate Pos |* x |- y
    >     uniplate (Neg x  ) = plate Neg |* x
    >     uniplate (Add x y) = plate Add |* x |* y
    >
    > instance Biplate Expr Expr where
    >     biplate = plateSelf
    >
    > instance Uniplate Stmt where
    >     uniplate (Seq x  ) = plate Seq ||* x
    >     uniplate (Sel x  ) = plate Sel ||+ x
    >     uniplate (Let x y) = plate Let |-  x |- y
    >
    > instance Biplate Stmt Stmt where
    >     biplate = plateSelf
    >
    > instance Biplate Stmt Expr where
    >     biplate (Seq x  ) = plate Seq ||+ x
    >     biplate (Sel x  ) = plate Sel ||* x
    >     biplate (Let x y) = plate Let |-  x |* y

    To define instances for abstract data types, such as @Map@ or @Set@ from the @containers@ package,
    use 'plateProject'.

    This module provides a few monomorphic instances of 'Uniplate' / 'Biplate'
    for common types available in the base library, but does not provide any polymorphic
    instances. Given only monomorphic instances it is trivial to ensure that all instances
    are disjoint, making it easier to add your own instances.

    When defining polymorphic instances, be carefully to mention all potential children.
    Consider @Biplate Int (Int, a)@ - this instance cannot be correct because it will fail
    to return both @Int@ values on @(Int,Int)@. There are some legitimate polymorphic instances,
    such as @Biplate a [a]@ and @Biplate a a@, but take care to avoid overlapping instances.
-}
module Data.Generics.Uniplate.Direct(
    module Data.Generics.Uniplate.Operations,
    -- * The Combinators
    plate, plateSelf,
    (|+), (|-), (|*), (||+), (||*),
    plateProject
    ) where

import Control.Arrow
import Data.Generics.Uniplate.Operations
import Data.Generics.Str
import Data.Ratio


type Type from to = (Str to, Str to -> from)

-- | The main combinator used to start the chain.
--
-- The following rule can be used for optimisation:
--
-- > plate Ctor |- x == plate (Ctor x)
{-# INLINE[1] plate #-}
plate :: from -> Type from to
plate :: from -> Type from to
plate from
f = (Str to
forall a. Str a
Zero, \Str to
_ -> from
f)


{-# RULES
"plate/-"    forall f x. plate f |- x = plate (f x)
"plate/+"    forall f x. plate f |+ x = platePlus f x
"plate/*"    forall f x. plate f |* x = plateStar f x #-}


{-# INLINE plateStar #-}
plateStar :: (to -> from) -> to -> Type from to
plateStar :: (to -> from) -> to -> Type from to
plateStar to -> from
f to
x = (to -> Str to
forall a. a -> Str a
One to
x, \(One to
x) -> to -> from
f to
x)

{-# INLINE platePlus #-}
platePlus :: Biplate item to => (item -> from) -> item -> Type from to
platePlus :: (item -> from) -> item -> Type from to
platePlus item -> from
f item
x = case item -> (Str to, Str to -> item)
forall from to. Biplate from to => from -> (Str to, Str to -> from)
biplate item
x of
                        (Str to
ys,Str to -> item
y_) -> (Str to
ys, \Str to
ys -> item -> from
f (item -> from) -> item -> from
forall a b. (a -> b) -> a -> b
$ Str to -> item
y_ Str to
ys)


-- | The field to the right is the target.
{-# INLINE[1] (|*) #-}
(|*) :: Type (to -> from) to -> to -> Type from to
|* :: Type (to -> from) to -> to -> Type from to
(|*) (Str to
xs,Str to -> to -> from
x_) to
y = (Str to -> Str to -> Str to
forall a. Str a -> Str a -> Str a
Two Str to
xs (to -> Str to
forall a. a -> Str a
One to
y),\(Two Str to
xs (One to
y)) -> Str to -> to -> from
x_ Str to
xs to
y)



-- | The field to the right may contain the target.
{-# INLINE[1] (|+) #-}
(|+) :: Biplate item to => Type (item -> from) to -> item -> Type from to
|+ :: Type (item -> from) to -> item -> Type from to
(|+) (Str to
xs,Str to -> item -> from
x_) item
y = case item -> (Str to, Str to -> item)
forall from to. Biplate from to => from -> (Str to, Str to -> from)
biplate item
y of
                      (Str to
ys,Str to -> item
y_) -> (Str to -> Str to -> Str to
forall a. Str a -> Str a -> Str a
Two Str to
xs Str to
ys, \(Two Str to
xs Str to
ys) -> Str to -> item -> from
x_ Str to
xs (Str to -> item
y_ Str to
ys))


-- | The field to the right /does not/ contain the target.
{-# INLINE[1] (|-) #-}
(|-) :: Type (item -> from) to -> item -> Type from to
|- :: Type (item -> from) to -> item -> Type from to
(|-) (Str to
xs,Str to -> item -> from
x_) item
y = (Str to
xs,\Str to
xs -> Str to -> item -> from
x_ Str to
xs item
y)


-- | The field to the right is a list of the type of the target
{-# INLINE (||*) #-}
(||*) :: Type ([to] -> from) to -> [to] -> Type from to
||* :: Type ([to] -> from) to -> [to] -> Type from to
(||*) (Str to
xs,Str to -> [to] -> from
x_) [to]
y = (Str to -> Str to -> Str to
forall a. Str a -> Str a -> Str a
Two Str to
xs ([to] -> Str to
forall a. [a] -> Str a
listStr [to]
y), \(Two Str to
xs Str to
ys) -> Str to -> [to] -> from
x_ Str to
xs (Str to -> [to]
forall a. Str a -> [a]
strList Str to
ys))


-- | The field to the right is a list of types which may contain the target
(||+) :: Biplate item to => Type ([item] -> from) to -> [item] -> Type from to
||+ :: Type ([item] -> from) to -> [item] -> Type from to
(||+) (Str to
xs,Str to -> [item] -> from
x_) [] = (Str to
xs, \Str to
xs -> Str to -> [item] -> from
x_ Str to
xs []) -- can eliminate a Two _ Zero in the base case
(||+) (Str to
xs,Str to -> [item] -> from
x_) (item
y:[item]
ys) = case (item -> [item] -> [item]) -> Type (item -> [item] -> [item]) to
forall from to. from -> Type from to
plate (:) Type (item -> [item] -> [item]) to
-> item -> Type ([item] -> [item]) to
forall item to from.
Biplate item to =>
Type (item -> from) to -> item -> Type from to
|+ item
y Type ([item] -> [item]) to -> [item] -> Type [item] to
forall item to from.
Biplate item to =>
Type ([item] -> from) to -> [item] -> Type from to
||+ [item]
ys of
                       (Str to
ys,Str to -> [item]
y_) -> (Str to -> Str to -> Str to
forall a. Str a -> Str a -> Str a
Two Str to
xs Str to
ys, \(Two Str to
xs Str to
ys) -> Str to -> [item] -> from
x_ Str to
xs (Str to -> [item]
y_ Str to
ys))


-- | Used for 'Biplate' definitions where both types are the same.
plateSelf :: to -> Type to to
plateSelf :: to -> Type to to
plateSelf to
x = (to -> Str to
forall a. a -> Str a
One to
x, \(One to
x) -> to
x)


-- | Write an instance in terms of a projection/injection pair. Usually used to define instances
--   for abstract containers such as Map:
--
-- > instance Biplate (Map.Map [Char] Int) Char where
-- >     biplate = plateProject Map.toList Map.fromList
--
--   If the types ensure that no operations will not change the keys
--   we can use the 'fromDistictAscList' function to reconstruct the Map:
--
-- > instance Biplate (Map.Map [Char] Int) Int where
-- >     biplate = plateProject Map.toAscList Map.fromDistinctAscList
plateProject :: Biplate item to => (from -> item) -> (item -> from) -> from -> Type from to
plateProject :: (from -> item) -> (item -> from) -> from -> Type from to
plateProject from -> item
into item -> from
outof = ((Str to -> item) -> Str to -> from)
-> (Str to, Str to -> item) -> Type from to
forall (a :: * -> * -> *) b c d.
Arrow a =>
a b c -> a (d, b) (d, c)
second (item -> from
outof (item -> from) -> (Str to -> item) -> Str to -> from
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ) ((Str to, Str to -> item) -> Type from to)
-> (from -> (Str to, Str to -> item)) -> from -> Type from to
forall b c a. (b -> c) -> (a -> b) -> a -> c
. item -> (Str to, Str to -> item)
forall from to. Biplate from to => from -> (Str to, Str to -> from)
biplate (item -> (Str to, Str to -> item))
-> (from -> item) -> from -> (Str to, Str to -> item)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. from -> item
into


instance Uniplate Int where uniplate :: Int -> (Str Int, Str Int -> Int)
uniplate Int
x = Int -> (Str Int, Str Int -> Int)
forall from to. from -> Type from to
plate Int
x
instance Uniplate Bool where uniplate :: Bool -> (Str Bool, Str Bool -> Bool)
uniplate Bool
x = Bool -> (Str Bool, Str Bool -> Bool)
forall from to. from -> Type from to
plate Bool
x
instance Uniplate Char where uniplate :: Char -> (Str Char, Str Char -> Char)
uniplate Char
x = Char -> (Str Char, Str Char -> Char)
forall from to. from -> Type from to
plate Char
x
instance Uniplate Integer where uniplate :: Integer -> (Str Integer, Str Integer -> Integer)
uniplate Integer
x = Integer -> (Str Integer, Str Integer -> Integer)
forall from to. from -> Type from to
plate Integer
x
instance Uniplate Double where uniplate :: Double -> (Str Double, Str Double -> Double)
uniplate Double
x = Double -> (Str Double, Str Double -> Double)
forall from to. from -> Type from to
plate Double
x
instance Uniplate Float where uniplate :: Float -> (Str Float, Str Float -> Float)
uniplate Float
x = Float -> (Str Float, Str Float -> Float)
forall from to. from -> Type from to
plate Float
x
instance Uniplate () where uniplate :: () -> (Str (), Str () -> ())
uniplate ()
x = () -> (Str (), Str () -> ())
forall from to. from -> Type from to
plate ()
x

instance Uniplate [Char] where
    uniplate :: [Char] -> (Str [Char], Str [Char] -> [Char])
uniplate (Char
x:[Char]
xs) = ([Char] -> [Char]) -> Type ([Char] -> [Char]) [Char]
forall from to. from -> Type from to
plate (Char
xChar -> [Char] -> [Char]
forall a. a -> [a] -> [a]
:) Type ([Char] -> [Char]) [Char]
-> [Char] -> (Str [Char], Str [Char] -> [Char])
forall to from. Type (to -> from) to -> to -> Type from to
|* [Char]
xs
    uniplate [Char]
x = [Char] -> (Str [Char], Str [Char] -> [Char])
forall from to. from -> Type from to
plate [Char]
x

instance Biplate [Char] Char where
    biplate :: [Char] -> (Str Char, Str Char -> [Char])
biplate (Char
x:[Char]
xs) = (Char -> [Char] -> [Char]) -> Type (Char -> [Char] -> [Char]) Char
forall from to. from -> Type from to
plate (:) Type (Char -> [Char] -> [Char]) Char
-> Char -> Type ([Char] -> [Char]) Char
forall to from. Type (to -> from) to -> to -> Type from to
|* Char
x Type ([Char] -> [Char]) Char
-> [Char] -> (Str Char, Str Char -> [Char])
forall to from. Type ([to] -> from) to -> [to] -> Type from to
||* [Char]
xs
    biplate [Char]
x = [Char] -> (Str Char, Str Char -> [Char])
forall from to. from -> Type from to
plate [Char]
x

instance Biplate [Char] [Char] where
    biplate :: [Char] -> (Str [Char], Str [Char] -> [Char])
biplate = [Char] -> (Str [Char], Str [Char] -> [Char])
forall to. to -> Type to to
plateSelf

instance Uniplate (Ratio Integer) where
    uniplate :: Ratio Integer
-> (Str (Ratio Integer), Str (Ratio Integer) -> Ratio Integer)
uniplate = Ratio Integer
-> (Str (Ratio Integer), Str (Ratio Integer) -> Ratio Integer)
forall from to. from -> Type from to
plate

instance Biplate (Ratio Integer) (Ratio Integer) where
    biplate :: Ratio Integer
-> (Str (Ratio Integer), Str (Ratio Integer) -> Ratio Integer)
biplate = Ratio Integer
-> (Str (Ratio Integer), Str (Ratio Integer) -> Ratio Integer)
forall to. to -> Type to to
plateSelf

instance Biplate (Ratio Integer) Integer where
    biplate :: Ratio Integer -> (Str Integer, Str Integer -> Ratio Integer)
biplate Ratio Integer
x = (Str Integer -> Str Integer -> Str Integer
forall a. Str a -> Str a -> Str a
Two (Integer -> Str Integer
forall a. a -> Str a
One (Ratio Integer -> Integer
forall a. Ratio a -> a
numerator Ratio Integer
x)) (Integer -> Str Integer
forall a. a -> Str a
One (Ratio Integer -> Integer
forall a. Ratio a -> a
denominator Ratio Integer
x)), \(Two (One Integer
n) (One Integer
d)) -> Integer
n Integer -> Integer -> Ratio Integer
forall a. Integral a => a -> a -> Ratio a
% Integer
d)