| Copyright | (c) The University of Glasgow CWI 2001--2003 |
|---|---|
| License | BSD-style (see the LICENSE file) |
| Maintainer | generics@haskell.org |
| Stability | experimental |
| Portability | non-portable (local universal quantification) |
| Safe Haskell | Safe |
| Language | Haskell98 |
Data.Generics.Schemes
Description
"Scrap your boilerplate" --- Generic programming in Haskell See http://www.cs.uu.nl/wiki/GenericProgramming/SYB. The present module provides frequently used generic traversal schemes.
Synopsis
- everywhere :: (forall a. Data a => a -> a) -> forall a. Data a => a -> a
- everywhere' :: (forall a. Data a => a -> a) -> forall a. Data a => a -> a
- everywhereBut :: GenericQ Bool -> GenericT -> GenericT
- everywhereM :: Monad m => GenericM m -> GenericM m
- somewhere :: MonadPlus m => GenericM m -> GenericM m
- everything :: (r -> r -> r) -> GenericQ r -> GenericQ r
- everythingBut :: (r -> r -> r) -> GenericQ (r, Bool) -> GenericQ r
- everythingWithContext :: s -> (r -> r -> r) -> GenericQ (s -> (r, s)) -> GenericQ r
- listify :: Typeable r => (r -> Bool) -> GenericQ [r]
- something :: GenericQ (Maybe u) -> GenericQ (Maybe u)
- synthesize :: s -> (t -> s -> s) -> GenericQ (s -> t) -> GenericQ t
- gsize :: Data a => a -> Int
- glength :: GenericQ Int
- gdepth :: GenericQ Int
- gcount :: GenericQ Bool -> GenericQ Int
- gnodecount :: GenericQ Int
- gtypecount :: Typeable a => a -> GenericQ Int
- gfindtype :: (Data x, Typeable y) => x -> Maybe y
Documentation
everywhere :: (forall a. Data a => a -> a) -> forall a. Data a => a -> a Source #
Apply a transformation everywhere in bottom-up manner
everywhere' :: (forall a. Data a => a -> a) -> forall a. Data a => a -> a Source #
Apply a transformation everywhere in top-down manner
everywhereBut :: GenericQ Bool -> GenericT -> GenericT Source #
Variation on everywhere with an extra stop condition
somewhere :: MonadPlus m => GenericM m -> GenericM m Source #
Apply a monadic transformation at least somewhere
everything :: (r -> r -> r) -> GenericQ r -> GenericQ r Source #
Summarise all nodes in top-down, left-to-right order
everythingBut :: (r -> r -> r) -> GenericQ (r, Bool) -> GenericQ r Source #
Variation of "everything" with an added stop condition
everythingWithContext :: s -> (r -> r -> r) -> GenericQ (s -> (r, s)) -> GenericQ r Source #
Summarise all nodes in top-down, left-to-right order, carrying some state down the tree during the computation, but not left-to-right to siblings.
listify :: Typeable r => (r -> Bool) -> GenericQ [r] Source #
Get a list of all entities that meet a predicate
something :: GenericQ (Maybe u) -> GenericQ (Maybe u) Source #
Look up a subterm by means of a maybe-typed filter
synthesize :: s -> (t -> s -> s) -> GenericQ (s -> t) -> GenericQ t Source #
Bottom-up synthesis of a data structure; 1st argument z is the initial element for the synthesis; 2nd argument o is for reduction of results from subterms; 3rd argument f updates the synthesised data according to the given term
gcount :: GenericQ Bool -> GenericQ Int Source #
Determine the number of all suitable nodes in a given term
gnodecount :: GenericQ Int Source #
Determine the number of all nodes in a given term