úή-     None%&:QRThe « type is very exciting, because if somebody ever gives you a value belonging to it, you know that you are already dead and in Heaven and that anything you want is yours.Similarly as there are many  sums, there are many  products, so we don't have  instances for tuples.' types which contains one thing, also Ò. There is nothing interesting to be gained by comparing one element of the boring type with another, because there is nothing to learn about an element of the boring type by giving it any of your attention. Boring Law:  == x Note: This is different class from Default. Default gives you some value, Boring gives you an unique value.3Also note, that we cannot have instances for e.g.  , as both ( a,  b) => Either a b and ( a,  b) => Either a b would be valid instances.BAnother useful trick, is that you can rewrite computations with  results, for example foo :: Int -> (), if you are sure that foo is total. +{-# RULES "less expensive" foo = boring #-})That's particularly useful with equality :~: proofs.If  is uninhabited then any ! that holds only values of type  is holding no values.If an index of  f is , f a is .If an index of  f is , f is isomorphic to . See also Settable class in lens. Type equality is  too.  a = a + 1,  0 + 1 = 1. CRecall regular expressions, kleene star of empty regexp is epsilon!        !"#$%boring-0-H7lhITttslp1cxVAtfi6YI Data.BoringAbsurdabsurdBoringboringvacuous boringRep untainted$fAbsurdIdentity$fAbsurdNonEmpty$fAbsurdEither $fAbsurdVoid $fBoring:~: $fBoringMaybe $fBoring[]$fBoring(,,,,) $fBoring(,,,) $fBoring(,,) $fBoring(,)$fBoringIdentity$fBoringTagged $fBoringConst $fBoringProxy $fBoring(->) $fBoring()base Data.EitherEitherGHC.BaseFunctor%adjunctions-4.3-X2U0XIVJySEv6aJWzZmLLData.Functor.Rep RepresentableData.Functor.IdentityIdentityMaybe