-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/
-- | Stack prisms
--
-- Haskell lens prisms that use stack types
@package stack-prism
@version 0.1.6
module Data.StackPrism
-- | A stack prism is a bidirectional isomorphism that is partial in the
-- backward direction. These prisms are compatible with the lens
-- library.
--
-- Stack prisms can express constructor-deconstructor pairs. For example:
--
--
-- nil :: StackPrism t ([a] :- t)
-- nil = stackPrism f g
-- where
-- f t = [] :- t
-- g ([] :- t) = Just t
-- g _ = Nothing
--
-- cons :: StackPrism (a :- [a] :- t) ([a] :- t)
-- cons = stackPrism f g
-- where
-- f (x :- xs :- t) = (x : xs) :- t
-- g ((x : xs) :- t) = Just (x :- xs :- t)
-- g _ = Nothing
--
--
-- Here :- can be read as 'cons', forming a stack of values. For
-- example, nil pushes [] onto the stack; or, in the
-- backward direction, tries to remove [] from the stack.
-- cons takes a head x and tail xs from the
-- stack and pushes x : xs onto the stack, or, in the backward
-- direction, tries to take x : xs from the stack and replaces
-- it with its two individual components.
--
-- Every constructor has its own stack prism version. You don't have to
-- write them by hand; you can automatically generate them, either using
-- Template Haskell (see module Data.StackPrism.TH) or using GHC
-- generic programming (see module Data.StackPrism.Generic).
type StackPrism a b = forall p f. (Choice p, Applicative f) => p a (f a) -> p b (f b)
-- | Construct a prism.
stackPrism :: (a -> b) -> (b -> Maybe a) -> StackPrism a b
-- | Apply a prism in forward direction.
forward :: StackPrism a b -> a -> b
-- | Apply a prism in backward direction.
backward :: StackPrism a b -> b -> Maybe a
-- | Heterogenous stack with a head and a tail. Or: an infix way to write
-- (,).
data (:-) h t
(:-) :: h -> t -> (:-) h t
instance GHC.Base.Functor ((Data.StackPrism.:-) h)
instance (GHC.Show.Show h, GHC.Show.Show t) => GHC.Show.Show (h Data.StackPrism.:- t)
instance (GHC.Classes.Eq h, GHC.Classes.Eq t) => GHC.Classes.Eq (h Data.StackPrism.:- t)
module Data.StackPrism.TH
-- | Derive stack prisms for a given datatype.
--
-- For example:
--
--
-- deriveStackPrisms ''Maybe
--
--
-- will create
--
--
-- _Just :: StackPrism (a :- t) (Maybe a :- t)
-- _Nothing :: StackPrism t (Nothing :- t)
--
--
-- together with their implementations.
deriveStackPrisms :: Name -> Q [Dec]
-- | Derive stack prisms given a function that derives variable names from
-- constructor names.
deriveStackPrismsWith :: (String -> String) -> Name -> Q [Dec]
-- | Derive stack prisms given a list of variable names, one for each
-- constructor.
deriveStackPrismsFor :: [String] -> Name -> Q [Dec]
-- | A stack prism is a bidirectional isomorphism that is partial in the
-- backward direction. These prisms are compatible with the lens
-- library.
--
-- Stack prisms can express constructor-deconstructor pairs. For example:
--
--
-- nil :: StackPrism t ([a] :- t)
-- nil = stackPrism f g
-- where
-- f t = [] :- t
-- g ([] :- t) = Just t
-- g _ = Nothing
--
-- cons :: StackPrism (a :- [a] :- t) ([a] :- t)
-- cons = stackPrism f g
-- where
-- f (x :- xs :- t) = (x : xs) :- t
-- g ((x : xs) :- t) = Just (x :- xs :- t)
-- g _ = Nothing
--
--
-- Here :- can be read as 'cons', forming a stack of values. For
-- example, nil pushes [] onto the stack; or, in the
-- backward direction, tries to remove [] from the stack.
-- cons takes a head x and tail xs from the
-- stack and pushes x : xs onto the stack, or, in the backward
-- direction, tries to take x : xs from the stack and replaces
-- it with its two individual components.
--
-- Every constructor has its own stack prism version. You don't have to
-- write them by hand; you can automatically generate them, either using
-- Template Haskell (see module Data.StackPrism.TH) or using GHC
-- generic programming (see module Data.StackPrism.Generic).
type StackPrism a b = forall p f. (Choice p, Applicative f) => p a (f a) -> p b (f b)
-- | Heterogenous stack with a head and a tail. Or: an infix way to write
-- (,).
data (:-) h t
(:-) :: h -> t -> (:-) h t
module Data.StackPrism.Generic
-- | Derive a list of stack prisms. For more information on the shape of a
-- PrismList, please see the documentation below.
mkPrismList :: (Generic a, MkPrismList (Rep a)) => StackPrisms a
-- | Convenient shorthand for a PrismList indexed by a type and its
-- generic representation.
type StackPrisms a = PrismList (Rep a) a
-- | A data family that is indexed on the building blocks from
-- representation types from GHC.Generics. It builds up to a
-- list of prisms, one for each constructor in the generic
-- representation. The list is wrapped in the unary constructor
-- PrismList. Within that constructor, the prisms are separated
-- by the right-associative binary infix constructor :&.
-- Finally, the individual prisms are wrapped in the unary constructor
-- P.
--
-- As an example, here is how to define the prisms nil and
-- cons for [a], which is an instance of
-- Generic:
--
--
-- nil :: StackPrism t ([a] :- t)
-- cons :: StackPrism (a :- [a] :- t) ([a] :- t)
-- PrismList (P nil :& P cons) = mkPrismList :: StackPrisms [a]
--
-- | A stack prism is a bidirectional isomorphism that is partial in the
-- backward direction. These prisms are compatible with the lens
-- library.
--
-- Stack prisms can express constructor-deconstructor pairs. For example:
--
--
-- nil :: StackPrism t ([a] :- t)
-- nil = stackPrism f g
-- where
-- f t = [] :- t
-- g ([] :- t) = Just t
-- g _ = Nothing
--
-- cons :: StackPrism (a :- [a] :- t) ([a] :- t)
-- cons = stackPrism f g
-- where
-- f (x :- xs :- t) = (x : xs) :- t
-- g ((x : xs) :- t) = Just (x :- xs :- t)
-- g _ = Nothing
--
--
-- Here :- can be read as 'cons', forming a stack of values. For
-- example, nil pushes [] onto the stack; or, in the
-- backward direction, tries to remove [] from the stack.
-- cons takes a head x and tail xs from the
-- stack and pushes x : xs onto the stack, or, in the backward
-- direction, tries to take x : xs from the stack and replaces
-- it with its two individual components.
--
-- Every constructor has its own stack prism version. You don't have to
-- write them by hand; you can automatically generate them, either using
-- Template Haskell (see module Data.StackPrism.TH) or using GHC
-- generic programming (see module Data.StackPrism.Generic).
type StackPrism a b = forall p f. (Choice p, Applicative f) => p a (f a) -> p b (f b)
-- | Heterogenous stack with a head and a tail. Or: an infix way to write
-- (,).
data (:-) h t
(:-) :: h -> t -> (:-) h t
instance Data.StackPrism.Generic.MkPrismList f => Data.StackPrism.Generic.MkPrismList (GHC.Generics.M1 GHC.Generics.D c f)
instance (Data.StackPrism.Generic.MkPrismList f, Data.StackPrism.Generic.MkPrismList g) => Data.StackPrism.Generic.MkPrismList (f GHC.Generics.:+: g)
instance Data.StackPrism.Generic.MkStackPrism f => Data.StackPrism.Generic.MkPrismList (GHC.Generics.M1 GHC.Generics.C c f)
instance Data.StackPrism.Generic.MkStackPrism GHC.Generics.U1
instance Data.StackPrism.Generic.MkStackPrism (GHC.Generics.K1 i a)
instance Data.StackPrism.Generic.MkStackPrism f => Data.StackPrism.Generic.MkStackPrism (GHC.Generics.M1 i c f)
instance (Data.StackPrism.Generic.MkStackPrism f, Data.StackPrism.Generic.MkStackPrism g) => Data.StackPrism.Generic.MkStackPrism (f GHC.Generics.:*: g)