{-# LANGUAGE CPP, NoImplicitPrelude, PackageImports #-} #if __GLASGOW_HASKELL__ >= 702 {-# LANGUAGE Trustworthy #-} #endif module Numeric.Natural.Compat ( module Base , minusNaturalMaybe ) where #if MIN_VERSION_base(4,8,0) import "base-compat" Numeric.Natural.Compat as Base #else import "nats" Numeric.Natural as Base import "this" Prelude.Compat -- | 'Natural' subtraction. Returns 'Nothing's for non-positive results. -- -- /Since: 4.18.0.0/ minusNaturalMaybe :: Natural -> Natural -> Maybe Natural minusNaturalMaybe x y | x < y = Nothing | otherwise = Just (x - y) #endif