| Copyright | (c) 2015-2016 Peter Trško |
|---|---|
| License | BSD3 |
| Maintainer | peter.trsko@gmail.com |
| Stability | experimental |
| Portability | CPP, DeriveFoldable, DeriveFunctor, DeriveDataTypeable, DeriveGeneric, DeriveTraversable, FlexibleInstances, NoImplicitPrelude, TypeFamilies |
| Safe Haskell | None |
| Language | Haskell2010 |
Data.Monoid.Endo.Apply
Description
ApplyEndo provides easier endomorphism evaluation in cases when there is an
"obvious" default value.
- newtype ApplyEndo t f a = ApplyEndo {
- applyEndo :: f a
- apply :: Applicative f => a -> Endo a -> ApplyEndo t f a
- applyF :: Functor f => a -> f (Endo a) -> ApplyEndo t f a
- data Mempty
- applyMempty :: Monoid a => ApplyEndo Mempty f a -> f a
- applyMempty_ :: Monoid a => ApplyEndo Mempty Identity a -> a
- joinApplyMempty :: (Monad m, Monoid a) => m (ApplyEndo Mempty m a) -> m a
- data Def
- applyDef :: (Applicative f, Default a) => ApplyEndo Def f a -> f a
- applyDef_ :: Default a => ApplyEndo Def Identity a -> a
- joinApplyDef :: (Monad m, Default a) => m (ApplyEndo Def m a) -> m a
- data Reader
- applyReader :: MonadReader r m => ApplyEndo Reader m r -> m r
- applyReaderWith :: MonadReader r m => (m r -> a) -> ApplyEndo Reader m r -> a
- joinApplyReader :: MonadReader r m => m (ApplyEndo Reader m r) -> m r
- data Modify
- applyModify :: MonadState s m => ApplyEndo Modify m s -> m s
- joinApplyModify :: MonadState s m => m (ApplyEndo Modify m s) -> m s
- data Modify'
- applyModify' :: MonadState r m => ApplyEndo Modify' m () -> m ()
- joinApplyModify' :: MonadState r m => m (ApplyEndo Modify' m r) -> m r
ApplyEndo
newtype ApplyEndo t f a Source #
There are cases when it is "obvious" what is the default value, which
should be modified by the endomorphism. This type is a result of such
endomorphism application and it uses phantom type t as distinguishing
property, which decides what is the correct "default value".
Instances
apply :: Applicative f => a -> Endo a -> ApplyEndo t f a Source #
Apply endomorphism using provided "default" value.
ApplyEndo Mempty
applyMempty :: Monoid a => ApplyEndo Mempty f a -> f a Source #
Constrained version of applyEndo. Usage example:
applyMempty . fromEndo :: (Applicativef,Monoida) =>Endoa -> f a
applyMempty_ :: Monoid a => ApplyEndo Mempty Identity a -> a Source #
Same as applyMempty, but Applicative functor is specialized to
Identity functor and evaluated.
Examples:
>>>fromEndoWith applyMempty_ $ foldEndo (+1) [(*10), (+42)] :: Int421>>>fromEndoWith applyMempty_ $ dualFoldEndo (+1) [(*10), (+42)] :: Int52
joinApplyMempty :: (Monad m, Monoid a) => m (ApplyEndo Mempty m a) -> m a Source #
Evaluates ApplyEndo in a Monad by joining it with the monad it
contains. It can be also viewed as a variant of applyMempty defined as:
joinApplyMempty= (>>=applyMempty)
ApplyEndo Def
Apply endomorphism to a default value def from Default. See also
following packages:
Both of those packages provide additional instances to Default type
class.
applyDef :: (Applicative f, Default a) => ApplyEndo Def f a -> f a Source #
Constrained version of applyEndo. Usage example:
applyDef . fromEndo :: (Applicativef,Defaulta) =>Endoa -> f a
applyDef_ :: Default a => ApplyEndo Def Identity a -> a Source #
Same as applyDef, but Applicative functor is specialized to Identity
functor and evaluated.
Examples:
>>>fromEndoWith applyDef_ $ foldEndo (+1) [(*10), (+42)] :: Int421>>>fromEndoWith applyDef_ $ dualFoldEndo (+1) [(*10), (+42)] :: Int52
ApplyEndo Reader
applyReader :: MonadReader r m => ApplyEndo Reader m r -> m r Source #
Evaluates ApplyEndo in terms of asks operation.
This (->) r is a valid MonadReader instance, therefore, this is a valid
use case:
>>>(applyReader . fromEndo $ foldEndo (*10) (+1)) 0 :: Int10
applyReaderWith :: MonadReader r m => (m r -> a) -> ApplyEndo Reader m r -> a Source #
Evaluates ApplyEndo in terms of asks operation and then
evaluates the resalt using provided function.
This (->) r is a valid MonadReader instance, therefore, this is a valid
use case:
>>>applyReaderWith ($ 0) . fromEndo $ foldEndo (*10) (+1) :: Int10
joinApplyReader :: MonadReader r m => m (ApplyEndo Reader m r) -> m r Source #
Evaluates ApplyEndo in a Monad by joining it with the monad it
contains. It can be also viewed as a variant of applyReader defined as:
joinApplyReader= (>>=applyReader)
ApplyEndo Modify
applyModify :: MonadState s m => ApplyEndo Modify m s -> m s Source #
joinApplyModify :: MonadState s m => m (ApplyEndo Modify m s) -> m s Source #
Evaluates ApplyEndo in a Monad by joining it with the monad it
contains. It can be also viewed as a variant of applyModify defined as:
joinApplyModify= (>>=applyModify)
ApplyEndo Modify'
Same as Modify, but strictness is implied.
Instances
applyModify' :: MonadState r m => ApplyEndo Modify' m () -> m () Source #
joinApplyModify' :: MonadState r m => m (ApplyEndo Modify' m r) -> m r Source #
Evaluates ApplyEndo in a Monad by joining it with the monad it
contains. It can be also viewed as a variant of applyModify' defined as:
joinApplyModify'= (>>=applyModify')