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Data.Generics.Aliases |

Portability | non-portable (local universal quantification)
Stability | experimental
Maintainer | libraries@haskell.org

Contents

Combinators to "make" generic functions via cast
Type synonyms for generic function types
Inredients of generic functions
Function combinators on generic functions
Type extension for unary type constructors

Description
"Scrap your boilerplate" --- Generic programming in Haskell See http://www.cs.vu.nl/boilerplate/. The present module provides a number of declarations for typical generic function types, corresponding type case, and others.
Synopsis

mkT :: (Typeable a, Typeable b) => (b -> b) -> a -> a
mkQ :: (Typeable a, Typeable b) => r -> (b -> r) -> a -> r
mkM :: (Monad m, Typeable a, Typeable b) => (b -> m b) -> a -> m a
mkMp :: (MonadPlus m, Typeable a, Typeable b) => (b -> m b) -> a -> m a
mkR :: (MonadPlus m, Typeable a, Typeable b) => m b -> m a
ext0 :: (Typeable a, Typeable b) => c a -> c b -> c a
extT :: (Typeable a, Typeable b) => (a -> a) -> (b -> b) -> a -> a
extQ :: (Typeable a, Typeable b) => (a -> q) -> (b -> q) -> a -> q
extM :: (Monad m, Typeable a, Typeable b) => (a -> m a) -> (b -> m b) -> a -> m a
extMp :: (MonadPlus m, Typeable a, Typeable b) => (a -> m a) -> (b -> m b) -> a -> m a
extB :: (Typeable a, Typeable b) => a -> b -> a
extR :: (Monad m, Typeable a, Typeable b) => m a -> m b -> m a
type GenericT = forall a . Data a => a -> a
type GenericQ r = forall a . Data a => a -> r
type GenericM m = forall a . Data a => a -> m a
type GenericB = forall a . Data a => a
type GenericR m = forall a . Data a => m a
type Generic c = forall a . Data a => a -> c a
data Generic' c = Generic' {

unGeneric' :: (Generic c)

}
newtype GenericT' = GT {

unGT :: (Data a => a -> a)

}
newtype GenericQ' r = GQ {

unGQ :: (GenericQ r)

}
newtype GenericM' m = GM {

unGM :: (Data a => a -> m a)

}
orElse :: Maybe a -> Maybe a -> Maybe a
recoverMp :: MonadPlus m => GenericM m -> GenericM m
recoverQ :: MonadPlus m => r -> GenericQ (m r) -> GenericQ (m r)
choiceMp :: MonadPlus m => GenericM m -> GenericM m -> GenericM m
choiceQ :: MonadPlus m => GenericQ (m r) -> GenericQ (m r) -> GenericQ (m r)
ext1T :: (Data d, Typeable1 t) => (forall d . Data d => d -> d) -> (forall d . Data d => t d -> t d) -> d -> d
ext1M :: (Monad m, Data d, Typeable1 t) => (forall d . Data d => d -> m d) -> (forall d . Data d => t d -> m (t d)) -> d -> m d
ext1Q :: (Data d, Typeable1 t) => (d -> q) -> (forall d . Data d => t d -> q) -> d -> q
ext1R :: (Monad m, Data d, Typeable1 t) => m d -> (forall d . Data d => m (t d)) -> m d

Combinators to "make" generic functions via cast

mkT :: (Typeable a, Typeable b) => (b -> b) -> a -> a | Source

Make a generic transformation; start from a type-specific case; preserve the term otherwise

mkQ :: (Typeable a, Typeable b) => r -> (b -> r) -> a -> r | Source

Make a generic query; start from a type-specific case; return a constant otherwise

mkM :: (Monad m, Typeable a, Typeable b) => (b -> m b) -> a -> m a | Source

Make a generic monadic transformation; start from a type-specific case; resort to return otherwise

mkMp :: (MonadPlus m, Typeable a, Typeable b) => (b -> m b) -> a -> m a | Source

Make a generic monadic transformation for MonadPlus; use "const mzero" (i.e., failure) instead of return as default.

mkR :: (MonadPlus m, Typeable a, Typeable b) => m b -> m a | Source

Make a generic builder; start from a type-specific ase; resort to no build (i.e., mzero) otherwise

ext0 :: (Typeable a, Typeable b) => c a -> c b -> c a | Source

Flexible type extension

extT :: (Typeable a, Typeable b) => (a -> a) -> (b -> b) -> a -> a | Source

Extend a generic transformation by a type-specific case

extQ :: (Typeable a, Typeable b) => (a -> q) -> (b -> q) -> a -> q | Source

Extend a generic query by a type-specific case

extM :: (Monad m, Typeable a, Typeable b) => (a -> m a) -> (b -> m b) -> a -> m a | Source

Extend a generic monadic transformation by a type-specific case

extMp :: (MonadPlus m, Typeable a, Typeable b) => (a -> m a) -> (b -> m b) -> a -> m a | Source

Extend a generic MonadPlus transformation by a type-specific case

extB :: (Typeable a, Typeable b) => a -> b -> a | Source

Extend a generic builder

extR :: (Monad m, Typeable a, Typeable b) => m a -> m b -> m a | Source

Extend a generic reader
Type synonyms for generic function types

type GenericT = forall a . Data a => a -> a | Source

Generic transformations, i.e., take an "a" and return an "a"

type GenericQ r = forall a . Data a => a -> r | Source

Generic queries of type "r", i.e., take any "a" and return an "r"

type GenericM m = forall a . Data a => a -> m a | Source

Generic monadic transformations, i.e., take an "a" and compute an "a"

type GenericB = forall a . Data a => a | Source

Generic builders i.e., produce an "a".

type GenericR m = forall a . Data a => m a | Source

Generic readers, say monadic builders, i.e., produce an "a" with the help of a monad "m".

type Generic c = forall a . Data a => a -> c a | Source

The general scheme underlying generic functions assumed by gfoldl; there are isomorphisms such as GenericT = Generic T.

data Generic' c | Source

Wrapped generic functions; recall: [Generic c] would be legal but [Generic' c] not.
Constructors

Generic' |

unGeneric' :: (Generic c) |

newtype GenericT' | Source

Other first-class polymorphic wrappers
Constructors

GT |

unGT :: (Data a => a -> a) |

newtype GenericQ' r | Source

Constructors

GQ |

unGQ :: (GenericQ r) |

newtype GenericM' m | Source

Constructors

GM |

unGM :: (Data a => a -> m a) |

Inredients of generic functions

orElse :: Maybe a -> Maybe a -> Maybe a | Source

Left-biased choice on maybies
Function combinators on generic functions

recoverMp :: MonadPlus m => GenericM m -> GenericM m | Source

Recover from the failure of monadic transformation by identity

recoverQ :: MonadPlus m => r -> GenericQ (m r) -> GenericQ (m r) | Source

Recover from the failure of monadic query by a constant

choiceMp :: MonadPlus m => GenericM m -> GenericM m -> GenericM m | Source

Choice for monadic transformations

choiceQ :: MonadPlus m => GenericQ (m r) -> GenericQ (m r) -> GenericQ (m r) | Source

Choice for monadic queries
Type extension for unary type constructors

ext1T :: (Data d, Typeable1 t) => (forall d . Data d => d -> d) -> (forall d . Data d => t d -> t d) -> d -> d | Source

Type extension of transformations for unary type constructors

ext1M :: (Monad m, Data d, Typeable1 t) => (forall d . Data d => d -> m d) -> (forall d . Data d => t d -> m (t d)) -> d -> m d | Source

Type extension of monadic transformations for type constructors

ext1Q :: (Data d, Typeable1 t) => (d -> q) -> (forall d . Data d => t d -> q) -> d -> q | Source

Type extension of queries for type constructors

ext1R :: (Monad m, Data d, Typeable1 t) => m d -> (forall d . Data d => m (t d)) -> m d | Source

Type extension of readers for type constructors
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