Commit 5748d428 authored by Joachim Breitner's avatar Joachim Breitner

fannkuch-redux: Implement Semigroup along with Monoid

so that it builds with GHC-8.3 post 8ae263c.
parent 999a46a1
......@@ -12,15 +12,17 @@ import Control.Concurrent
import Control.Monad
import System.Environment
import Foreign hiding (rotate)
import Data.Monoid
import Data.Semigroup
type Perm = Ptr Word8
data F = F {-# UNPACK #-} !Int {-# UNPACK #-} !Int
instance Semigroup F where
F s1 m1 <> F s2 m2 = F (s1 + s2) (max m1 m2)
instance Monoid F where
mempty = F 0 0
F s1 m1 `mappend` F s2 m2 = F (s1 + s2) (max m1 m2)
incPtr = (`advancePtr` 1)
decPtr = (`advancePtr` (-1))
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