Copyright | (c) Andrey Mokhov 2018-2024 |
---|---|
License | MIT (see the file LICENSE) |
Maintainer | andrey.mokhov@gmail.com |
Stability | experimental |
Safe Haskell | Safe-Inferred |
Language | Haskell2010 |
This is a library for selective applicative functors, or just selective functors for short, an abstraction between applicative functors and monads, introduced in this paper: https://dl.acm.org/doi/10.1145/3341694.
This module defines free selective functors using the ideas from the Sjoerd Visscher's package 'free-functors': https://hackage.haskell.org/package/free-functors-1.0.1/docs/Data-Functor-HFree.html.
Synopsis
- newtype Select f a = Select (forall g. Selective g => (forall x. f x -> g x) -> g a)
- liftSelect :: f a -> Select f a
- getPure :: Select f a -> Maybe a
- getEffects :: Functor f => Select f a -> [f ()]
- getNecessaryEffects :: Functor f => Select f a -> [f ()]
- runSelect :: Selective g => (forall x. f x -> g x) -> Select f a -> g a
- foldSelect :: Monoid m => (forall x. f x -> m) -> Select f a -> m
Free selective functors
Free selective functors.
liftSelect :: f a -> Select f a Source #
Lift a functor into a free selective computation.
Static analysis
getPure :: Select f a -> Maybe a Source #
Extract the resulting value if there are no necessary effects.
getEffects :: Functor f => Select f a -> [f ()] Source #
Collect all possible effects in the order they appear in a free selective computation.
getNecessaryEffects :: Functor f => Select f a -> [f ()] Source #
Extract all necessary effects in the order they appear in a free selective computation.
runSelect :: Selective g => (forall x. f x -> g x) -> Select f a -> g a Source #
Given a natural transformation from f
to g
, this gives a canonical
natural transformation from Select f
to g
. Note that here we rely on the
fact that g
is a lawful selective functor.
foldSelect :: Monoid m => (forall x. f x -> m) -> Select f a -> m Source #
Concatenate all effects of a free selective computation.