Data.MonoTraversable

Type classes mirroring standard typeclasses, but working with monomorphic containers.

The motivation is that some commonly used data types (i.e., ByteString and Text) do not allow for instances of typeclasses like Functor and Foldable, since they are monomorphic structures. This module allows both monomorphic and polymorphic data types to be instances of the same typeclasses.

All of the laws for the polymorphic typeclasses apply to their monomorphic cousins. Thus, even though a MonoFunctor instance for Set could theoretically be defined, it is omitted since it could violate the functor law of omap f . omap g = omap (f . g).

Note that all typeclasses have been prefixed with Mono, and functions have been prefixed with o. The mnemonic for o is "only one", or alternatively "it's mono, but m is overused in Haskell, so we'll use the second letter instead." (Agreed, it's not a great mangling scheme, input is welcome!)

Documentation

type family Element mono

Type family for getting the type of the elements of a monomorphic container.

Instances

type Element ByteString = Word8

type Element ByteString = Word8

type Element IntSet = Int

type Element Text = Char

type Element Text = Char

type Element [a] = a

type Element (IO a) = a

type Element (Identity a) = a

type Element (ZipList a) = a

type Element (Maybe a) = a

type Element (IntMap a) = a

type Element (Set e) = e

type Element (Tree a) = a

type Element (Seq a) = a

type Element (ViewL a) = a

type Element (ViewR a) = a

type Element (DList a) = a

type Element (Option a) = a

type Element (NonEmpty a) = a

type Element (HashSet e) = e

type Element (Vector a) = a

type Element (Vector a) = a

type Element (Vector a) = a

type Element (r -> a) = a

type Element (Either a b) = b

type Element (a, b) = b

type Element (Const m a) = a

type Element (WrappedMonad m a) = a

type Element (IdentityT m a) = a

type Element (Map k v) = v

type Element (ListT m a) = a

type Element (WrappedApplicative f a) = a

type Element (MaybeApply f a) = a

type Element (Arg a b) = b

type Element (MaybeT m a) = a

type Element (HashMap k v) = v

type Element (MinLen nat mono) = Element mono

type Element (WrappedArrow a b c) = c

type Element (TracedT m w a) = a

type Element (StoreT s w a) = a

type Element (EnvT e w a) = a

type Element (Cokleisli w a b) = b

type Element (ContT r m a) = a

type Element (ReaderT r m a) = a

type Element (StateT s m a) = a

type Element (StateT s m a) = a

type Element (ErrorT e m a) = a

type Element (WriterT w m a) = a

type Element (WriterT w m a) = a

type Element (Compose f g a) = a

type Element (Static f a b) = b

type Element (Product f g a) = a

type Element (RWST r w s m a) = a

type Element (RWST r w s m a) = a

class MonoFunctor mono where

Monomorphic containers that can be mapped over.

Minimal complete definition

Nothing

Methods

omap :: (Element mono -> Element mono) -> mono -> mono

Map over a monomorphic container

Instances

MonoFunctor ByteString

MonoFunctor ByteString

MonoFunctor Text

MonoFunctor Text

MonoFunctor [a]

MonoFunctor (IO a)

MonoFunctor (Identity a)

MonoFunctor (ZipList a)

MonoFunctor (Maybe a)

MonoFunctor (IntMap a)

MonoFunctor (Tree a)

MonoFunctor (Seq a)

MonoFunctor (ViewL a)

MonoFunctor (ViewR a)

MonoFunctor (DList a)

MonoFunctor (Option a)

MonoFunctor (NonEmpty a)

MonoFunctor (Vector a)

Unbox a => MonoFunctor (Vector a)

Storable a => MonoFunctor (Vector a)

MonoFunctor (r -> a)

MonoFunctor (Either a b)

MonoFunctor (a, b)

MonoFunctor (Const m a)

Monad m => MonoFunctor (WrappedMonad m a)

Functor m => MonoFunctor (IdentityT m a)

MonoFunctor (Map k v)

Functor m => MonoFunctor (ListT m a)

Functor f => MonoFunctor (WrappedApplicative f a)

Functor f => MonoFunctor (MaybeApply f a)

MonoFunctor (Arg a b)

Functor m => MonoFunctor (MaybeT m a)

MonoFunctor (HashMap k v)

MonoFunctor mono => MonoFunctor (MinLen nat mono)

Arrow a => MonoFunctor (WrappedArrow a b c)

Functor w => MonoFunctor (TracedT m w a)

Functor w => MonoFunctor (StoreT s w a)

Functor w => MonoFunctor (EnvT e w a)

MonoFunctor (Cokleisli w a b)

Functor m => MonoFunctor (ContT r m a)

Functor m => MonoFunctor (ReaderT r m a)

Functor m => MonoFunctor (StateT s m a)

Functor m => MonoFunctor (StateT s m a)

Functor m => MonoFunctor (ErrorT e m a)

Functor m => MonoFunctor (WriterT w m a)

Functor m => MonoFunctor (WriterT w m a)

(Functor f, Functor g) => MonoFunctor (Compose f g a)

Functor f => MonoFunctor (Static f a b)

(Functor f, Functor g) => MonoFunctor (Product f g a)

Functor m => MonoFunctor (RWST r w s m a)

Functor m => MonoFunctor (RWST r w s m a)

class MonoFoldable mono where

Monomorphic containers that can be folded.

Minimal complete definition

Nothing

Methods

ofoldMap :: Monoid m => (Element mono -> m) -> mono -> m

Map each element of a monomorphic container to a Monoid and combine the results.

ofoldr :: (Element mono -> b -> b) -> b -> mono -> b

Right-associative fold of a monomorphic container.

ofoldl' :: (a -> Element mono -> a) -> a -> mono -> a

Strict left-associative fold of a monomorphic container.

otoList :: mono -> [Element mono]

Convert a monomorphic container to a list.

oall :: (Element mono -> Bool) -> mono -> Bool

Are all of the elements in a monomorphic container converted to booleans True?

oany :: (Element mono -> Bool) -> mono -> Bool

Are any of the elements in a monomorphic container converted to booleans True?

onull :: mono -> Bool

Is the monomorphic container empty?

olength :: mono -> Int

Length of a monomorphic container, returns a Int.

olength64 :: mono -> Int64

Length of a monomorphic container, returns a Int64.

ocompareLength :: Integral i => mono -> i -> Ordering

Compare the length of a monomorphic container and a given number.

otraverse_ :: (MonoFoldable mono, Applicative f) => (Element mono -> f b) -> mono -> f ()

Map each element of a monomorphic container to an action, evaluate these actions from left to right, and ignore the results.

ofor_ :: (MonoFoldable mono, Applicative f) => mono -> (Element mono -> f b) -> f ()

ofor_ is otraverse_ with its arguments flipped.

omapM_ :: (MonoFoldable mono, Monad m) => (Element mono -> m ()) -> mono -> m ()

Map each element of a monomorphic container to a monadic action, evaluate these actions from left to right, and ignore the results.

oforM_ :: (MonoFoldable mono, Monad m) => mono -> (Element mono -> m ()) -> m ()

oforM_ is omapM_ with its arguments flipped.

ofoldlM :: (MonoFoldable mono, Monad m) => (a -> Element mono -> m a) -> a -> mono -> m a

Monadic fold over the elements of a monomorphic container, associating to the left.

ofoldMap1Ex :: Semigroup m => (Element mono -> m) -> mono -> m

Map each element of a monomorphic container to a semigroup, and combine the results.

Note: this is a partial function. On an empty MonoFoldable, it will throw an exception.

See ofoldMap1 from Data.MinLen for a total version of this function.

ofoldr1Ex :: (Element mono -> Element mono -> Element mono) -> mono -> Element mono

Right-associative fold of a monomorphic container with no base element.

Note: this is a partial function. On an empty MonoFoldable, it will throw an exception.

See ofoldr1Ex from Data.MinLen for a total version of this function.

ofoldl1Ex' :: (Element mono -> Element mono -> Element mono) -> mono -> Element mono

Strict left-associative fold of a monomorphic container with no base element.

Note: this is a partial function. On an empty MonoFoldable, it will throw an exception.

See ofoldl1Ex' from Data.MinLen for a total version of this function.

headEx :: mono -> Element mono

Get the first element of a monomorphic container.

Note: this is a partial function. On an empty MonoFoldable, it will throw an exception.

See head from Data.MinLen for a total version of this function.

lastEx :: mono -> Element mono

Get the last element of a monomorphic container.

Note: this is a partial function. On an empty MonoFoldable, it will throw an exception.

See 'Data.MinLen.last from Data.MinLen for a total version of this function.

unsafeHead :: mono -> Element mono

Equivalent to headEx.

unsafeLast :: mono -> Element mono

Equivalent to lastEx.

maximumByEx :: (Element mono -> Element mono -> Ordering) -> mono -> Element mono

Get the maximum element of a monomorphic container, using a supplied element ordering function.

Note: this is a partial function. On an empty MonoFoldable, it will throw an exception.

See maximiumBy from Data.MinLen for a total version of this function.

minimumByEx :: (Element mono -> Element mono -> Ordering) -> mono -> Element mono

Get the minimum element of a monomorphic container, using a supplied element ordering function.

Note: this is a partial function. On an empty MonoFoldable, it will throw an exception.

See minimumBy from Data.MinLen for a total version of this function.

Instances

MonoFoldable ByteString

MonoFoldable ByteString

MonoFoldable IntSet

MonoFoldable Text

MonoFoldable Text

MonoFoldable [a]

MonoFoldable (Identity a)

MonoFoldable (Maybe a)

MonoFoldable (IntMap a)

MonoFoldable (Set e)

MonoFoldable (Tree a)

MonoFoldable (Seq a)

MonoFoldable (ViewL a)

MonoFoldable (ViewR a)

MonoFoldable (DList a)

MonoFoldable (Option a)

MonoFoldable (NonEmpty a)

MonoFoldable (HashSet e)

MonoFoldable (Vector a)

Unbox a => MonoFoldable (Vector a)

Storable a => MonoFoldable (Vector a)

MonoFoldable (Either a b)

MonoFoldable (a, b)

MonoFoldable (Const m a)

Foldable f => MonoFoldable (IdentityT f a)

MonoFoldable (Map k v)

Foldable f => MonoFoldable (ListT f a)

Foldable f => MonoFoldable (MaybeT f a)

MonoFoldable (HashMap k v)

MonoFoldable mono => MonoFoldable (MinLen nat mono)

Foldable f => MonoFoldable (ErrorT e f a)

Foldable f => MonoFoldable (WriterT w f a)

Foldable f => MonoFoldable (WriterT w f a)

(Foldable f, Foldable g) => MonoFoldable (Compose f g a)

(Foldable f, Foldable g) => MonoFoldable (Product f g a)

headMay :: MonoFoldable mono => mono -> Maybe (Element mono)

Safe version of headEx.

Returns Nothing instead of throwing an exception when encountering an empty monomorphic container.

lastMay :: MonoFoldable mono => mono -> Maybe (Element mono)

Safe version of lastEx.

Returns Nothing instead of throwing an exception when encountering an empty monomorphic container.

osum :: (MonoFoldable mono, Num (Element mono)) => mono -> Element mono

osum computes the sum of the numbers of a monomorphic container.

oproduct :: (MonoFoldable mono, Num (Element mono)) => mono -> Element mono

oproduct computes the product of the numbers of a monomorphic container.

oand :: (Element mono ~ Bool, MonoFoldable mono) => mono -> Bool

Are all of the elements True?

Since 0.6.0

oor :: (Element mono ~ Bool, MonoFoldable mono) => mono -> Bool

Are any of the elements True?

Since 0.6.0

class (MonoFoldable mono, Monoid mono) => MonoFoldableMonoid mono where

A typeclass for monomorphic containers that are Monoids.

Minimal complete definition

Nothing

Methods

oconcatMap :: (Element mono -> mono) -> mono -> mono

Map a function over a monomorphic container and combine the results.

Instances

MonoFoldableMonoid ByteString

MonoFoldableMonoid ByteString

MonoFoldableMonoid Text

MonoFoldableMonoid Text

(MonoFoldable (t a), Monoid (t a)) => MonoFoldableMonoid (t a)

class (MonoFoldable mono, Eq (Element mono)) => MonoFoldableEq mono where

A typeclass for monomorphic containers whose elements are an instance of Eq.

Minimal complete definition

Nothing

Methods

oelem :: Element mono -> mono -> Bool

Checks if the monomorphic container includes the supplied element.

onotElem :: Element mono -> mono -> Bool

Checks if the monomorphic container does not include the supplied element.

Instances

MonoFoldableEq ByteString

MonoFoldableEq ByteString

MonoFoldableEq IntSet

MonoFoldableEq Text

MonoFoldableEq Text

Eq a => MonoFoldableEq [a]

Eq a => MonoFoldableEq (Identity a)

Eq a => MonoFoldableEq (Maybe a)

Eq a => MonoFoldableEq (IntMap a)

(Eq a, Ord a) => MonoFoldableEq (Set a)

Eq a => MonoFoldableEq (Tree a)

Eq a => MonoFoldableEq (Seq a)

Eq a => MonoFoldableEq (ViewL a)

Eq a => MonoFoldableEq (ViewR a)

Eq a => MonoFoldableEq (DList a)

Eq a => MonoFoldableEq (Option a)

Eq a => MonoFoldableEq (NonEmpty a)

Eq a => MonoFoldableEq (HashSet a)

Eq a => MonoFoldableEq (Vector a)

(Eq a, Unbox a) => MonoFoldableEq (Vector a)

(Eq a, Storable a) => MonoFoldableEq (Vector a)

Eq b => MonoFoldableEq (Either a b)

Eq b => MonoFoldableEq (a, b)

Eq a => MonoFoldableEq (Const m a)

(Eq a, Foldable f) => MonoFoldableEq (IdentityT f a)

Eq v => MonoFoldableEq (Map k v)

(Eq a, Foldable f) => MonoFoldableEq (ListT f a)

(Eq a, Foldable f) => MonoFoldableEq (MaybeT f a)

Eq v => MonoFoldableEq (HashMap k v)

MonoFoldableEq mono => MonoFoldableEq (MinLen nat mono)

(Eq a, Foldable f) => MonoFoldableEq (ErrorT e f a)

(Eq a, Foldable f) => MonoFoldableEq (WriterT w f a)

(Eq a, Foldable f) => MonoFoldableEq (WriterT w f a)

(Eq a, Foldable f, Foldable g) => MonoFoldableEq (Compose f g a)

(Eq a, Foldable f, Foldable g) => MonoFoldableEq (Product f g a)

class (MonoFoldable mono, Ord (Element mono)) => MonoFoldableOrd mono where

A typeclass for monomorphic containers whose elements are an instance of Ord.

Minimal complete definition

Nothing

Methods

maximumEx :: mono -> Element mono

Get the minimum element of a monomorphic container.

Note: this is a partial function. On an empty MonoFoldable, it will throw an exception.

See maximum from Data.MinLen for a total version of this function.

minimumEx :: mono -> Element mono

Get the maximum element of a monomorphic container.

Note: this is a partial function. On an empty MonoFoldable, it will throw an exception.

See minimum from Data.MinLen for a total version of this function.

Instances

MonoFoldableOrd ByteString

MonoFoldableOrd ByteString

MonoFoldableOrd IntSet

MonoFoldableOrd Text

MonoFoldableOrd Text

Ord a => MonoFoldableOrd [a]

Ord a => MonoFoldableOrd (Identity a)

Ord a => MonoFoldableOrd (Maybe a)

Ord a => MonoFoldableOrd (IntMap a)

Ord e => MonoFoldableOrd (Set e)

Ord a => MonoFoldableOrd (Tree a)

Ord a => MonoFoldableOrd (Seq a)

Ord a => MonoFoldableOrd (ViewL a)

Ord a => MonoFoldableOrd (ViewR a)

Ord a => MonoFoldableOrd (DList a)

Ord a => MonoFoldableOrd (Option a)

Ord a => MonoFoldableOrd (NonEmpty a)

Ord e => MonoFoldableOrd (HashSet e)

Ord a => MonoFoldableOrd (Vector a)

(Unbox a, Ord a) => MonoFoldableOrd (Vector a)

(Ord a, Storable a) => MonoFoldableOrd (Vector a)

Ord b => MonoFoldableOrd (Either a b)

Ord b => MonoFoldableOrd (a, b)

Ord a => MonoFoldableOrd (Const m a)

(Ord a, Foldable f) => MonoFoldableOrd (IdentityT f a)

Ord v => MonoFoldableOrd (Map k v)

(Ord a, Foldable f) => MonoFoldableOrd (ListT f a)

(Ord a, Foldable f) => MonoFoldableOrd (MaybeT f a)

Ord v => MonoFoldableOrd (HashMap k v)

MonoFoldableOrd mono => MonoFoldableOrd (MinLen nat mono)

(Ord a, Foldable f) => MonoFoldableOrd (ErrorT e f a)

(Ord a, Foldable f) => MonoFoldableOrd (WriterT w f a)

(Ord a, Foldable f) => MonoFoldableOrd (WriterT w f a)

(Ord a, Foldable f, Foldable g) => MonoFoldableOrd (Compose f g a)

(Ord a, Foldable f, Foldable g) => MonoFoldableOrd (Product f g a)

maximumMay :: MonoFoldableOrd mono => mono -> Maybe (Element mono)

Safe version of maximumEx.

Returns Nothing instead of throwing an exception when encountering an empty monomorphic container.

maximumByMay :: MonoFoldable mono => (Element mono -> Element mono -> Ordering) -> mono -> Maybe (Element mono)

Safe version of maximumByEx.

Returns Nothing instead of throwing an exception when encountering an empty monomorphic container.

minimumMay :: MonoFoldableOrd mono => mono -> Maybe (Element mono)

Safe version of minimumEx.

Returns Nothing instead of throwing an exception when encountering an empty monomorphic container.

minimumByMay :: MonoFoldable mono => (Element mono -> Element mono -> Ordering) -> mono -> Maybe (Element mono)

Safe version of minimumByEx.

Returns Nothing instead of throwing an exception when encountering an empty monomorphic container.

class (MonoFunctor mono, MonoFoldable mono) => MonoTraversable mono where

Monomorphic containers that can be traversed from left to right.

Minimal complete definition

Nothing

Methods

otraverse :: Applicative f => (Element mono -> f (Element mono)) -> mono -> f mono

Map each element of a monomorphic container to an action, evaluate these actions from left to right, and collect the results.

omapM :: Monad m => (Element mono -> m (Element mono)) -> mono -> m mono

Map each element of a monomorphic container to a monadic action, evaluate these actions from left to right, and collect the results.

Instances

MonoTraversable ByteString

MonoTraversable ByteString

MonoTraversable Text

MonoTraversable Text

MonoTraversable [a]

MonoTraversable (Identity a)

MonoTraversable (Maybe a)

MonoTraversable (IntMap a)

MonoTraversable (Tree a)

MonoTraversable (Seq a)

MonoTraversable (ViewL a)

MonoTraversable (ViewR a)

MonoTraversable (DList a)

MonoTraversable (Option a)

MonoTraversable (NonEmpty a)

MonoTraversable (Vector a)

Unbox a => MonoTraversable (Vector a)

Storable a => MonoTraversable (Vector a)

MonoTraversable (Either a b)

MonoTraversable (a, b)

MonoTraversable (Const m a)

Traversable f => MonoTraversable (IdentityT f a)

MonoTraversable (Map k v)

Traversable f => MonoTraversable (ListT f a)

Traversable f => MonoTraversable (MaybeT f a)

MonoTraversable (HashMap k v)

MonoTraversable mono => MonoTraversable (MinLen nat mono)

Traversable f => MonoTraversable (ErrorT e f a)

Traversable f => MonoTraversable (WriterT w f a)

Traversable f => MonoTraversable (WriterT w f a)

(Traversable f, Traversable g) => MonoTraversable (Compose f g a)

(Traversable f, Traversable g) => MonoTraversable (Product f g a)

ofor :: (MonoTraversable mono, Applicative f) => mono -> (Element mono -> f (Element mono)) -> f mono

ofor is otraverse with its arguments flipped.

oforM :: (MonoTraversable mono, Monad f) => mono -> (Element mono -> f (Element mono)) -> f mono

oforM is omapM with its arguments flipped.

ofoldlUnwrap :: MonoFoldable mono => (x -> Element mono -> x) -> x -> (x -> b) -> mono -> b

A strict left fold, together with an unwrap function.

This is convenient when the accumulator value is not the same as the final expected type. It is provided mainly for integration with the foldl package, to be used in conjunction with purely.

Since 0.3.1

ofoldMUnwrap :: (Monad m, MonoFoldable mono) => (x -> Element mono -> m x) -> m x -> (x -> m b) -> mono -> m b

A monadic strict left fold, together with an unwrap function.

Similar to foldlUnwrap, but allows monadic actions. To be used with impurely from foldl.

Since 0.3.1

class MonoPointed mono where

Typeclass for monomorphic containers that an element can be lifted into.

For any MonoFunctor, the following law holds:

omap f . opoint = opoint . f

Minimal complete definition

Nothing

Methods

opoint :: Element mono -> mono

Lift an element into a monomorphic container.

opoint is the same as pure for an Applicative

Instances

MonoPointed ByteString

MonoPointed ByteString

MonoPointed IntSet

MonoPointed Text

MonoPointed Text

MonoPointed [a]

MonoPointed (IO a)

MonoPointed (Identity a)

MonoPointed (ZipList a)

MonoPointed (Maybe a)

MonoPointed (Set a)

MonoPointed (Tree a)

MonoPointed (Seq a)

MonoPointed (ViewL a)

MonoPointed (ViewR a)

MonoPointed (DList a)

MonoPointed (Option a)

MonoPointed (NonEmpty a)

Hashable a => MonoPointed (HashSet a)

MonoPointed (Vector a)

Unbox a => MonoPointed (Vector a)

Storable a => MonoPointed (Vector a)

MonoPointed (r -> a)

MonoPointed (Either a b)

Monoid a => MonoPointed (a, b)

Monoid m => MonoPointed (Const m a)

Monad m => MonoPointed (WrappedMonad m a)

Applicative m => MonoPointed (IdentityT m a)

Applicative m => MonoPointed (ListT m a)

Applicative f => MonoPointed (WrappedApplicative f a)

MonoPointed (MaybeApply f a)

Applicative f => MonoPointed (MaybeT f a)

MonoPointed mono => MonoPointed (MinLen (Succ Zero) mono)

MonoPointed mono => MonoPointed (MinLen Zero mono)

Arrow a => MonoPointed (WrappedArrow a b c)

MonoPointed (Cokleisli w a b)

MonoPointed (ContT r m a)

Applicative m => MonoPointed (ReaderT r m a)

Applicative m => MonoPointed (StateT s m a)

Applicative m => MonoPointed (StateT s m a)

Applicative m => MonoPointed (ErrorT e m a)

(Monoid w, Applicative m) => MonoPointed (WriterT w m a)

(Monoid w, Applicative m) => MonoPointed (WriterT w m a)

(Applicative f, Applicative g) => MonoPointed (Compose f g a)

Applicative f => MonoPointed (Static f a b)

(Applicative f, Applicative g) => MonoPointed (Product f g a)

(Monoid w, Applicative m) => MonoPointed (RWST r w s m a)

(Monoid w, Applicative m) => MonoPointed (RWST r w s m a)

class MonoFunctor mono => MonoComonad mono where

Typeclass for monomorphic containers where it is always okay to "extract" a value from with oextract, and where you can extrapolate any "extracting" function to be a function on the whole part with oextend.

oextend and oextract should work together following the laws:

oextend oextract      = id
oextract . oextend f  = f
oextend f . oextend g = oextend (f . oextend g)

As an intuition, oextend f uses f to "build up" a new mono with pieces from the old one received by f.

Minimal complete definition

Nothing

Methods

oextract :: mono -> Element mono

Extract an element from mono. Can be thought of as a dual concept to opoint.

oextend :: (mono -> Element mono) -> mono -> mono

Extend a mono -> Element mono function to be a mono -> mono; that is, builds a new mono from the old one by using pieces glimpsed from the given function.

Instances

MonoComonad (Identity a)

MonoComonad (Tree a)

MonoComonad (ViewL a)

MonoComonad (ViewR a)

MonoComonad (NonEmpty a)

Monoid m => MonoComonad (m -> a)

MonoComonad (e, a)

Comonad w => MonoComonad (IdentityT w a)

MonoComonad (Arg a b)

IsSequence mono => MonoComonad (MinLen (Succ Zero) mono)

oextract is head.

For oextend f, the new mono is populated by applying f to successive tails of the original mono.

For example, for MinLen (Succ Zero) [Int], or NonNull [Int]:

oextend f [1,2,3,4,5] = [ f [1, 2, 3, 4, 5]
                          , f [2, 3, 4, 5]
                          , f [3, 4, 5]
                          , f [4, 5]
                          , f [5]
                          ]

Meant to be a direct analogy to the instance for NonEmpty a.

(Comonad w, Monoid m) => MonoComonad (TracedT m w a)

Comonad w => MonoComonad (StoreT s w a)

Comonad w => MonoComonad (EnvT e w a)