Safe Haskell | Trustworthy |
---|---|
Language | Haskell2010 |
Zipping and unzipping of functors with non-uniform shapes.
Documentation
class Functor f => Semialign f where Source #
Functors supporting an align
operation that takes the union of
non-uniform shapes.
Minimal definition: either align
or alignWith
.
Laws
The laws of align
and zip
resemble lattice laws.
There is a plenty of laws, but they are simply satisfied.
And an addition property if f
is Foldable
,
which tries to enforce align
-feel:
neither values are duplicated nor lost.
Note: join
f x = f x x
Idempotency
join align ≡ fmap (join These)
Commutativity
align x y ≡ swap <$> align y x
Associativity
align x (align y z) ≡ assoc <$> align (align x y) z
With
alignWith f a b ≡ f <$> align a b
Functoriality
align (f <$> x) (g <$> y) ≡ bimap f g <$> align x y
Alignedness, if f
is Foldable
toList x ≡ toListOf (folded . here) (align x y) ≡ mapMaybe justHere (toList (align x y))
And an addition property if f
is Foldable
,
which tries to enforce align
-feel:
neither values are duplicated nor lost.
toList x = toListOf (folded . here) (align x y) = mapMaybe justHere (toList (align x y))
align :: f a -> f b -> f (These a b) Source #
Analogous to
, combines two structures by taking the union of
their shapes and using zip
to hold the elements.These
alignWith :: (These a b -> c) -> f a -> f b -> f c Source #
Analogous to
, combines two structures by taking the union of
their shapes and combining the elements with the given function.zipWith
Instances
Semialign [] Source # | |
Semialign Maybe Source # | |
Semialign Option Source # | |
Semialign ZipList Source # |
|
Semialign Identity Source # | |
Semialign NonEmpty Source # | |
Semialign IntMap Source # | |
Semialign Tree Source # | |
Semialign Seq Source # | |
Semialign Vector Source # | |
Semialign (Proxy :: Type -> Type) Source # | |
Ord k => Semialign (Map k) Source # | |
(Eq k, Hashable k) => Semialign (HashMap k) Source # | |
Monad m => Semialign (Stream m) Source # | |
Semialign (Tagged b) Source # | |
Monad m => Semialign (Bundle m v) Source # | |
Semialign ((->) e :: Type -> Type) Source # | |
(Semialign f, Semialign g) => Semialign (Product f g) Source # | |
(Semialign f, Semialign g) => Semialign (Compose f g) Source # | |
class Semialign f => Zip f where Source #
Functors supporting a zip
operation that takes the intersection of
non-uniform shapes.
Minimal definition: either zip
or zipWith
.
Idempotency
join zip ≡ fmap (join (,))
Commutativity
zip x y ≡ swap <$> zip y x
Associativity
zip x (zip y z) ≡ assoc <$> zip (zip x y) z
Absorption
fst <$> zip xs (align xs ys) ≡ xs toThis <$> align xs (zip xs ys) ≡ This <$> xs where toThis (This a) = This a toThis (These a _) = This a toThis (That b) = That b
With
zipWith f a b ≡ f <$> zip a b
Functoriality
zip (f <$> x) (g <$> y) ≡ bimap f g <$> zip x y
Zippyness
fmap fst (zip x x) ≡ x fmap snd (zip x x) ≡ x zip (fmap fst x) (fmap snd x) ≡ x
Distributivity
align (zip xs ys) zs ≡ undistrThesePair <$> zip (align xs zs) (align ys zs) distrPairThese <$> zip (align xs ys) zs ≡ align (zip xs zs) (zip ys zs) zip (align xs ys) zs ≡ undistrPairThese <$> align (zip xs zs) (zip ys zs)
Note, the following doesn't hold:
distrThesePair <$> align (zip xs ys) zs ≢ zip (align xs zs) (align ys zs)
when xs = []
and ys = zs = [0]
, then
the left hand side is "only" [(
,
but the right hand side is That
0, That
0)][(
.That
0, These
0 0)]
zip :: f a -> f b -> f (a, b) Source #
Combines two structures by taking the intersection of their shapes and using pair to hold the elements.
zipWith :: (a -> b -> c) -> f a -> f b -> f c Source #
Combines two structures by taking the intersection of their shapes and combining the elements with the given function.
Instances
Zip [] Source # | |
Zip Maybe Source # | |
Zip Option Source # | |
Zip ZipList Source # | |
Zip Identity Source # | |
Zip NonEmpty Source # | |
Zip IntMap Source # | |
Zip Tree Source # | |
Zip Seq Source # | |
Zip Vector Source # | |
Zip (Proxy :: Type -> Type) Source # | |
Ord k => Zip (Map k) Source # | |
(Eq k, Hashable k) => Zip (HashMap k) Source # | |
Monad m => Zip (Stream m) Source # | |
Zip (Tagged b) Source # | |
Monad m => Zip (Bundle m v) Source # | |
Zip ((->) e :: Type -> Type) Source # | |
(Zip f, Zip g) => Zip (Product f g) Source # | |
(Zip f, Zip g) => Zip (Compose f g) Source # | |
class Zip f => Repeat f where Source #
Zippable functors supporting left and right units
Unit
fst <$> zip xs (repeat y) ≡ xs snd <$> zip (repeat x) ys ≡ ys
Instances
Repeat [] Source # | |
Defined in Data.Semialign.Internal | |
Repeat Maybe Source # | |
Defined in Data.Semialign.Internal | |
Repeat Option Source # | |
Defined in Data.Semialign.Internal | |
Repeat ZipList Source # | |
Defined in Data.Semialign.Internal | |
Repeat Identity Source # | |
Defined in Data.Semialign.Internal | |
Repeat NonEmpty Source # | |
Defined in Data.Semialign.Internal | |
Repeat Tree Source # | |
Defined in Data.Semialign.Internal | |
Repeat (Proxy :: Type -> Type) Source # | |
Defined in Data.Semialign.Internal | |
Repeat (Tagged b) Source # | |
Defined in Data.Semialign.Internal | |
Repeat ((->) e :: Type -> Type) Source # | |
Defined in Data.Semialign.Internal | |
(Repeat f, Repeat g) => Repeat (Product f g) Source # | |
Defined in Data.Semialign.Internal | |
(Repeat f, Repeat g) => Repeat (Compose f g) Source # | |
Defined in Data.Semialign.Internal |
class Zip f => Unzip f where Source #
Right inverse of zip
.
This class is definable for every Functor
. See unzipDefault
.
Laws
uncurry zip (unzip xs) ≡ xs unzip (zip xs xs) ≡ (xs, xs)
Note:
unzip (zip xs ys) ≢ (xs, _) or (_, ys)
For sequence-like types this holds, but for Map-like it doesn't.
Instances
Unzip [] Source # | |
Unzip Maybe Source # | |
Unzip Option Source # | |
Unzip ZipList Source # | |
Unzip Identity Source # | |
Unzip NonEmpty Source # | |
Unzip IntMap Source # | |
Unzip Tree Source # | |
Unzip Seq Source # | |
Unzip Vector Source # | |
Unzip (Proxy :: Type -> Type) Source # | |
Ord k => Unzip (Map k) Source # | |
(Eq k, Hashable k) => Unzip (HashMap k) Source # | |
Unzip (Tagged b) Source # | |
(Unzip f, Unzip g) => Unzip (Product f g) Source # | |
(Unzip f, Unzip g) => Unzip (Compose f g) Source # | |
unzipDefault :: Functor f => f (a, b) -> (f a, f b) Source #
Instances
Functor f => Functor (Zippy f) Source # | |
Repeat f => Applicative (Zippy f) Source # | |
Zip f => Apply (Zippy f) Source # | |
Eq (f a) => Eq (Zippy f a) Source # | |
Ord (f a) => Ord (Zippy f a) Source # | |
Defined in Data.Zip | |
Read (f a) => Read (Zippy f a) Source # | |
Show (f a) => Show (Zippy f a) Source # | |
(Zip f, Semigroup a) => Semigroup (Zippy f a) Source # | |
(Repeat f, Monoid a) => Monoid (Zippy f a) Source # | |