{- Data/Singletons/Instances.hs (c) Richard Eisenberg 2013 eir@cis.upenn.edu This (internal) module contains the main class definitions for singletons, re-exported from various places. -} {-# LANGUAGE RankNTypes, TypeInType, GADTs, TypeFamilies, FlexibleContexts, TemplateHaskell, ScopedTypeVariables, UndecidableInstances, TypeOperators, FlexibleInstances #-} {-# OPTIONS_GHC -fno-warn-orphans #-} module Data.Singletons.Prelude.Instances where import Data.Singletons.Single import Data.Singletons.Util -- some useful singletons $(genSingletons basicTypes) $(singDecideInstances basicTypes) -- basic definitions we need right away $(singletonsOnly [d| foldl :: forall a b. (b -> a -> b) -> b -> [a] -> b foldl f z0 xs0 = lgo z0 xs0 where lgo :: b -> [a] -> b lgo z [] = z lgo z (x:xs) = lgo (f z x) xs |])