Use (<>) from Data.Monoid if compiler version is recent enough

ekmett · Aug 27, 2015 · dd40c61 · dd40c61
1 parent 34208ff
commit dd40c61
Showing 1 changed file with 13 additions and 7 deletions.
diff --git a/Text/PrettyPrint/ANSI/Leijen.hs b/Text/PrettyPrint/ANSI/Leijen.hs
@@ -111,7 +111,7 @@ module Text.PrettyPrint.ANSI.Leijen (
    -- * Character documents
    lparen, rparen, langle, rangle, lbrace, rbrace, lbracket, rbracket,
    squote, dquote, semi, colon, comma, space, dot, backslash, equals,
-   
+
    -- * Colorisation combinators
    black, red, green, yellow, blue, magenta, cyan, white,
    dullblack, dullred, dullgreen, dullyellow, dullblue, dullmagenta, dullcyan, dullwhite,
@@ -120,7 +120,7 @@ module Text.PrettyPrint.ANSI.Leijen (
 
    -- * Emboldening combinators
    bold, debold,
-   
+
    -- * Underlining combinators
    underline, deunderline,
 
@@ -151,13 +151,17 @@ import System.Console.ANSI (Color(..), ColorIntensity(..), ConsoleLayer(..),
 
 import Data.String (IsString(..))
 import Data.Maybe (catMaybes)
-#if __GLASGOW_HASKELL__ < 710
+#if __GLASGOW_HASKELL__ >= 710
+import Data.Monoid ((<>))
+#elif __GLASGOW_HASKELL__ >= 704
+import Data.Monoid (Monoid, mappend, mconcat, mempty, (<>))
+#else
 import Data.Monoid (Monoid, mappend, mconcat, mempty)
+infixr 6 <>
 #endif
 
-
+infixr 6 <+>
 infixr 5 </>,<//>,<$>,<$$>
-infixr 6 <>,<+>
 
 
 -----------------------------------------------------------
@@ -216,7 +220,7 @@ encloseSep left right sep ds
     = case ds of
         []  -> left <> right
         [d] -> left <> d <> right
-        _   -> align (cat (zipWith (<>) (left : repeat sep) ds) <> right) 
+        _   -> align (cat (zipWith (<>) (left : repeat sep) ds) <> right)
 
 
 -----------------------------------------------------------
@@ -345,11 +349,13 @@ fold :: (Doc -> Doc -> Doc) -> [Doc] -> Doc
 fold f []       = empty
 fold f ds       = foldr1 f ds
 
+#if __GLASGOW_HASKELL__ < 704
 -- | The document @(x \<\> y)@ concatenates document @x@ and document
 -- @y@. It is an associative operation having 'empty' as a left and
 -- right unit.  (infixr 6)
 (<>) :: Doc -> Doc -> Doc
 x <> y          = x `beside` y
+#endif
 
 -- | The document @(x \<+\> y)@ concatenates document @x@ and @y@ with a
 -- @space@ in between.  (infixr 6)
@@ -775,7 +781,7 @@ data SimpleDoc  = SFail
 -- from base gained a Monoid instance (<http://hackage.haskell.org/trac/ghc/ticket/4378>):
 instance Monoid Doc where
     mempty = empty
-    mappend = (<>)
+    mappend = beside
     mconcat = hcat
 
 -- MCB: also added when "pretty" got the corresponding instances: