The List
class and actions for lists
- class (MonadPlus l, Monad (ItemM l)) => List l where
- data ListItem l a
- cons :: MonadPlus m => a -> m a -> m a
- fromList :: MonadPlus m => [a] -> m a
- filter :: MonadPlus m => (a -> Bool) -> m a -> m a
- repeat :: MonadPlus m => a -> m a
- takeWhile :: List l => (a -> Bool) -> l a -> l a
- genericTake :: (Integral i, List l) => i -> l a -> l a
- scanl :: List l => (a -> b -> a) -> a -> l b -> l a
- transpose :: List l => l (l a) -> l (l a)
- zip :: List l => l a -> l b -> l (a, b)
- zipWith :: List l => (a -> b -> c) -> l a -> l b -> l c
- foldrL :: List l => (a -> ItemM l b -> ItemM l b) -> ItemM l b -> l a -> ItemM l b
- foldlL :: List l => (a -> b -> a) -> a -> l b -> ItemM l a
- toList :: List l => l a -> ItemM l [a]
- lengthL :: (Integral i, List l) => l a -> ItemM l i
- lastL :: List l => l a -> ItemM l a
- merge2On :: (Ord b, List l) => (a -> b) -> l a -> l a -> l a
- mergeOn :: (Ord b, List l) => (a -> b) -> l (l a) -> l a
- execute :: List l => l a -> ItemM l ()
- joinM :: List l => l (ItemM l a) -> l a
- transformListMonad :: (List l, List k) => (forall x. ItemM l x -> ItemM k x) -> l a -> k a
Documentation
The List typeclass
class (MonadPlus l, Monad (ItemM l)) => List l whereSource
A class for list types. Every list has an underlying monad.
List operations for MonadPlus
fromList :: MonadPlus m => [a] -> m aSource
Convert a list to a MonadPlus
> fromList [] :: Maybe Int Nothing > fromList [5] :: Maybe Int Just 5
filter :: MonadPlus m => (a -> Bool) -> m a -> m aSource
filter for any MonadPlus
> filter (> 5) (Just 3) Nothing
Standard list operations
genericTake :: (Integral i, List l) => i -> l a -> l aSource
Non standard List operations
foldrL :: List l => (a -> ItemM l b -> ItemM l b) -> ItemM l b -> l a -> ItemM l bSource
foldr for List
s.
the result and 'right side' values are monadic actions.
toList :: List l => l a -> ItemM l [a]Source
An action to transform a List
to a list
> runIdentity $ toList "hello!" "hello!"
lengthL :: (Integral i, List l) => l a -> ItemM l iSource
Consume a list (execute its actions) and return its length
> runIdentity $ lengthL [1,2,3] 3
lastL :: List l => l a -> ItemM l aSource
Consume all items and return the last one
> runIdentity $ lastL "hello" 'o'
merge2On :: (Ord b, List l) => (a -> b) -> l a -> l a -> l aSource
Merge two lists sorted by a criteria given the criteria
> merge2On id "01568" "239" "01235689"
mergeOn :: (Ord b, List l) => (a -> b) -> l (l a) -> l aSource
Merge many lists sorted by a criteria given the criteria
> mergeOn length [["hi", "hey", "hello"], ["cat", "falcon"], ["banana", "cucumber"]] ["hi","cat","hey","hello","banana","falcon","cucumber"]
Operations useful for monadic lists
joinM :: List l => l (ItemM l a) -> l aSource
Transform a list of actions to a list of their results
> joinM [Identity 4, Identity 7] [4,7]
Convert between List types