From a08f6e400772899b9b0fc16befc50391cd70696b Mon Sep 17 00:00:00 2001
From: Felix Yan <felixonmars@archlinux.org>
Date: Fri, 18 May 2018 16:24:41 +0800
Subject: [PATCH] GHC 8.4 support

---
 src/Extension/Data/Bounded.hs       | 10 ++++-
 src/Extension/Data/Monoid.hs        | 14 +++---
 src/Logic/Connectives.hs            |  4 +-
 src/Text/PrettyPrint/Class.hs       |  4 +-
 src/Text/PrettyPrint/Html.hs        |  6 ++-
 11 files changed, 79 insertions(+), 48 deletions(-)


diff --git a/src/Extension/Data/Bounded.hs b/src/Extension/Data/Bounded.hs
index 5f166006..f416a44c 100644
--- a/src/Extension/Data/Bounded.hs
+++ b/src/Extension/Data/Bounded.hs
@@ -11,19 +11,25 @@ module Extension.Data.Bounded (
   ) where
 
 -- import Data.Monoid
+import Data.Semigroup
 
 -- | A newtype wrapper for a monoid of the maximum of a bounded type.
 newtype BoundedMax a = BoundedMax {getBoundedMax :: a}
     deriving( Eq, Ord, Show )
 
+instance (Ord a, Bounded a) => Semigroup (BoundedMax a) where
+    BoundedMax x <> BoundedMax y = BoundedMax (max x y)
+
 instance (Ord a, Bounded a) => Monoid (BoundedMax a) where
     mempty                                  = BoundedMax minBound
-    (BoundedMax x) `mappend` (BoundedMax y) = BoundedMax (max x y)
+    mappend = (<>)
 
 -- | A newtype wrapper for a monoid of the minimum of a bounded type.
 newtype BoundedMin a = BoundedMin {getBoundedMin :: a}
     deriving( Eq, Ord, Show )
 
+instance (Ord a, Bounded a) => Semigroup (BoundedMin a) where
+    BoundedMin x <> BoundedMin y = BoundedMin (min x y)
+
 instance (Ord a, Bounded a) => Monoid (BoundedMin a) where
     mempty                                  = BoundedMin maxBound
-    (BoundedMin x) `mappend` (BoundedMin y) = BoundedMin (min x y)
\ No newline at end of file
diff --git a/src/Extension/Data/Monoid.hs b/src/Extension/Data/Monoid.hs
index 83655c34..9ce2f91b 100644
--- a/src/Extension/Data/Monoid.hs
+++ b/src/Extension/Data/Monoid.hs
@@ -18,6 +18,7 @@ module Extension.Data.Monoid (
   ) where
 
 import Data.Monoid
+import Data.Semigroup
 
 #if __GLASGOW_HASKELL__ < 704
 
@@ -38,10 +39,13 @@ newtype MinMax a = MinMax { getMinMax :: Maybe (a, a) }
 minMaxSingleton :: a -> MinMax a
 minMaxSingleton x = MinMax (Just (x, x))
 
+instance Ord a => Semigroup (MinMax a) where
+    MinMax Nothing             <> y                          = y
+    x                          <> MinMax Nothing             = x
+    MinMax (Just (xMin, xMax)) <> MinMax (Just (yMin, yMax)) =
+       MinMax (Just (min xMin yMin, max xMax yMax))
+
+
 instance Ord a => Monoid (MinMax a) where
     mempty = MinMax Nothing
-
-    MinMax Nothing             `mappend` y                          = y
-    x                          `mappend` MinMax Nothing             = x
-    MinMax (Just (xMin, xMax)) `mappend` MinMax (Just (yMin, yMax)) =
-       MinMax (Just (min xMin yMin, max xMax yMax))
+    mappend = (<>)
diff --git a/src/Logic/Connectives.hs b/src/Logic/Connectives.hs
index 2e441172..7206cc2c 100644
--- a/src/Logic/Connectives.hs
+++ b/src/Logic/Connectives.hs
@@ -23,12 +23,12 @@ import Control.DeepSeq
 
 -- | A conjunction of atoms of type a.
 newtype Conj a = Conj { getConj :: [a] }
-  deriving (Monoid, Foldable, Traversable, Eq, Ord, Show, Binary,
+  deriving (Monoid, Semigroup, Foldable, Traversable, Eq, Ord, Show, Binary,
             Functor, Applicative, Monad, Alternative, MonadPlus, Typeable, Data, NFData)
 
 -- | A disjunction of atoms of type a.
 newtype Disj a = Disj { getDisj :: [a] }
-  deriving (Monoid, Foldable, Traversable, Eq, Ord, Show, Binary,
+  deriving (Monoid, Semigroup, Foldable, Traversable, Eq, Ord, Show, Binary,
             Functor, Applicative, Monad, Alternative, MonadPlus, Typeable, Data, NFData)
 
 instance MonadDisj Disj where
diff --git a/src/Text/PrettyPrint/Class.hs b/src/Text/PrettyPrint/Class.hs
index f5eb42fe..13be6515 100644
--- a/src/Text/PrettyPrint/Class.hs
+++ b/src/Text/PrettyPrint/Class.hs
@@ -187,9 +187,11 @@ instance Document Doc where
   nest i (Doc d) = Doc $ P.nest i d
   caseEmptyDoc yes no (Doc d) = if P.isEmpty d then yes else no
 
+instance Semigroup Doc where
+    Doc d1 <> Doc d2 = Doc $ (P.<>) d1 d2
+
 instance Monoid Doc where
     mempty = Doc $ P.empty
-    mappend (Doc d1) (Doc d2) = Doc $ (P.<>) d1 d2
   
 ------------------------------------------------------------------------------
 -- Additional combinators
diff --git a/src/Text/PrettyPrint/Html.hs b/src/Text/PrettyPrint/Html.hs
index 3de5e307..10103eb7 100644
--- a/src/Text/PrettyPrint/Html.hs
+++ b/src/Text/PrettyPrint/Html.hs
@@ -90,7 +90,7 @@ attribute (key,value) = " " ++ key ++ "=\"" ++ escapeHtmlEntities value ++ "\""
 
 -- | A 'Document' transformer that adds proper HTML escaping.
 newtype HtmlDoc d = HtmlDoc { getHtmlDoc :: d }
-    deriving( Monoid )
+    deriving( Monoid, Semigroup )
 
 -- | Wrap a document such that HTML markup can be added without disturbing the
 -- layout.
@@ -182,9 +182,11 @@ getNoHtmlDoc = runIdentity . unNoHtmlDoc
 instance NFData d => NFData (NoHtmlDoc d) where
     rnf = rnf . getNoHtmlDoc
 
+instance Semigroup d => Semigroup (NoHtmlDoc d) where
+  (<>) = liftA2 (<>)
+
 instance Monoid d => Monoid (NoHtmlDoc d) where
   mempty = pure mempty
-  mappend = liftA2 mappend
 
 instance Document d => Document (NoHtmlDoc d) where
   char = pure . char