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Updated ListTr haddock

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Marcin Szamotulski 2019-09-05 09:02:05 +02:00
parent 510c758b59
commit 3405380fbf
1 changed files with 7 additions and 5 deletions
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12
src/Control/Category/Free/Internal.hs
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@ -89,12 +89,14 @@ instance Category f => Monoid (Op f o o) where
mappend = (<>)
#endif
-- |
-- Free category encoded as a recursive data type, in a simlar way as
-- @'Control.Monad.Free.Free'@. You can use @'FreeAlgebra2'@ class instance:
-- | Simple representation of a free category by using type aligned
-- lists. This is not a surprise as free monoids can be represented by
-- lists (up to laziness)
--
-- prop> liftFree2 @Cat :: f a b -> Cat f ab
-- prop> foldNatFree2 @Cat :: Category d => (forall x y. f x y -> d x y) -> Cat f a b -> d a b
-- 'ListTr' has @'FreeAlgebra2'@ class instance:
--
-- prop> liftFree2 @ListTr :: f a b -> ListTr f ab
-- prop> foldNatFree2 @ListTr :: Category d => (forall x y. f x y -> d x y) -> ListTr f a b -> d a b
--
-- The same performance concerns that apply to @'Control.Monad.Free.Free'@
-- apply to this encoding of a free category.