Coyoneda docs - lets add some math ;) #82
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paf31
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Apr 15, 2017
src/Data/Coyoneda.purs
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| @@ -78,6 +102,21 @@ unCoyoneda :: forall f g a. (forall b. (b -> a) -> f b -> g a) -> Coyoneda f a - | |||
| unCoyoneda f (Coyoneda e) = runExists (\(CoyonedaF k fi) -> f k fi) e | |||
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| -- | Lift a value described by the type constructor `f` to `Coyoneda f`. | |||
| -- | | |||
| -- | Note that for any `f` `liftCoyoneda` has a right inverse | |||
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Good catch. For any f it has a left inverse.
ps. I will have more pr like this one.
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Looks good to me, just one minor nitpick. Thanks! |
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Thanks! |
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I was reading through Coyoneda, and made some math notes. They might be useful for others, especially for ones that are learning PureScript and are not super familiar with category theory to have enough intuition to derive all the laws that one gets for free from the structures.