haskell-src-exts-1.17.0: tests/examples/RCategory.hs.prettyprinter.golden

{-# LANGUAGE TypeFamilies, ConstraintKinds, MultiParamTypeClasses
  #-}
module Control.RCategory where
import qualified Prelude
import GHC.Prim

infixr 9 .

infixr 1 >>>, <<<

class RCategory cat where
        type RCategoryCtxt cat a b :: Constraint
        
        id :: RCategoryCtxt cat a a => cat a a
        
        (.) ::
              (RCategoryCtxt cat b c, RCategoryCtxt cat a b,
               RCategoryCtxt cat a c) =>
              cat b c -> cat a b -> cat a c

{-# RULES
"identity/left" forall p . id . p = p
"identity/right" forall p . p . id = p
 #-}

instance RCategory (->) where
        type RCategoryCtxt (->) a a = ()
        id = Prelude.id
        (.) = (Prelude..)

(<<<) ::
        (RCategoryCtxt cat a c, RCategoryCtxt cat a b,
         RCategoryCtxt cat b c, RCategory cat) =>
        cat b c -> cat a b -> cat a c
(<<<) = (.)

(>>>) ::
        (RCategoryCtxt cat a c, RCategoryCtxt cat a b,
         RCategoryCtxt cat b c, RCategory cat) =>
        cat a b -> cat b c -> cat a c
f >>> g = g . f