polysemy-1.7.1.0: Higher-order, low-boilerplate free monads.
Safe HaskellNone
LanguageHaskell2010

Polysemy.Internal.CustomErrors

Synopsis

Documentation

type WhenStuck expr b = IfStuck expr b NoErrorFcf Source #

Like IfStuck, but specialized to the case when you don't want to do anything if expr isn't stuck.

type FirstOrder (e :: Effect) fn = UnlessStuck e (FirstOrderErrorFcf e fn) Source #

This constraint gives helpful error messages if you attempt to use a first-order combinator with a higher-order type.

type family (l :: k1) <> (r :: k2) :: ErrorMessage where ... infixl 5 Source #

Equations

l <> r = ToErrorMessage l :<>: ToErrorMessage r 

type family (t :: k1) % (b :: k2) :: ErrorMessage where ... infixr 4 Source #

Equations

t % b = ToErrorMessage t :$$: ToErrorMessage b