Merge pull request #42 from expipiplus1/ghc8

Add Show1 instances for base 4.9

Nix/Expr/Types.hs

@@ -6,6 +6,7 @@
 {-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE TemplateHaskell #-}
 -- | The nix expression type and supporting types.
 module Nix.Expr.Types where
 
@@ -13,8 +14,8 @@ import           Control.Monad hiding (forM_, mapM, sequence)
 import           Data.Data
 import           Data.Fix
 import           Data.Foldable
-import           Data.Functor.Classes (Show1(..))
+import           Data.Functor.Classes (Show1(..), showsUnaryWith, liftShowsPrec2)
-import           Data.Map (Map)
+import           Data.Map (Map, toList)
 import           Data.Text (Text, pack)
 import           Data.Traversable
 import           GHC.Exts
@@ -22,6 +23,7 @@ import           GHC.Generics
 import           Nix.Atoms
 import           Prelude hiding (readFile, concat, concatMap, elem, mapM,
                                  sequence, minimum, foldr)
+import           Text.Show.Deriving
 
 -- | The main nix expression type. This is polymorphic so that it can be made
 -- a functor, which allows us to traverse expressions and map functions over
@@ -72,14 +74,12 @@ data NExprF r
   -- ^ Assert that the first returns true before evaluating the second.
   deriving (Ord, Eq, Generic, Typeable, Data, Functor, Foldable, Traversable, Show)
 
-instance Show1 NExprF where
-  showsPrec1 = showsPrec
-
 -- | We make an `IsString` for expressions, where the string is interpreted
 -- as an identifier. This is the most common use-case...
 instance IsString NExpr where
   fromString = Fix . NSym . fromString
 
+
 -- | The monomorphic expression type is a fixed point of the polymorphic one.
 type NExpr = Fix NExprF
 
@@ -116,6 +116,27 @@ data ParamSet r
   deriving (Ord, Eq, Generic, Typeable, Data, Functor, Show,
             Foldable, Traversable)
 
+-- It's not possible to derive this automatically as there is no Show1 instance
+-- for Map. We define one locally here.
+instance Show1 ParamSet where
+  liftShowsPrec sp sl p =
+    let liftShowsPrecMap :: (Int -> a -> ShowS)
+                         -> ([a] -> ShowS)
+                         -> Int
+                         -> Map Text a
+                         -> ShowS
+        liftShowsPrecMap spMap slMap pMap m =
+          showsUnaryWith (liftShowsPrec (liftShowsPrec spMap slMap)
+                                        (liftShowList spMap slMap))
+                         "fromList" pMap (Data.Map.toList m)
+        showNamedMap s =
+          showsUnaryWith (liftShowsPrecMap (liftShowsPrec sp sl)
+                                           (liftShowList sp sl))
+                         s p
+    in \case
+      FixedParamSet m    -> showNamedMap "FixedParamSet" m
+      VariadicParamSet m -> showNamedMap "VariadicParamSet" m
+
 -- | 'Antiquoted' represents an expression that is either
 -- antiquoted (surrounded by ${...}) or plain (not antiquoted).
 data Antiquoted v r = Plain !v | Antiquoted !r
@@ -166,7 +187,14 @@ data NKeyName r
 instance IsString (NKeyName r) where
   fromString = StaticKey . fromString
 
--- | Deriving this instance automatically is not possible because @r@
+-- Deriving this instance automatically is not possible because @r@
+-- occurs not only as last argument in @Antiquoted (NString r) r@
+instance Show1 NKeyName where
+  liftShowsPrec sp sl p = \case
+    DynamicKey a -> showsUnaryWith (liftShowsPrec2 (liftShowsPrec sp sl) (liftShowList sp sl) sp sl) "DynamicKey" p a
+    StaticKey t  -> showsUnaryWith showsPrec "StaticKey" p t
+
+-- Deriving this instance automatically is not possible because @r@
 -- occurs not only as last argument in @Antiquoted (NString r) r@
 instance Functor NKeyName where
   fmap = fmapDefault
@@ -215,3 +243,10 @@ data NBinaryOp
 paramName :: Params r -> Maybe Text
 paramName (Param n) = Just n
 paramName (ParamSet _ n) = n
+
+$(deriveShow1 ''NExprF)
+$(deriveShow1 ''NString)
+$(deriveShow1 ''Params)
+$(deriveShow1 ''Binding)
+$(deriveShow1 ''Antiquoted)
+$(deriveShow2 ''Antiquoted)

Nix/Expr/Types/Annotated.hs

@@ -7,6 +7,8 @@
 {-# LANGUAGE FlexibleInstances  #-}
 {-# LANGUAGE LambdaCase         #-}
 {-# LANGUAGE OverloadedStrings  #-}
+{-# LANGUAGE TemplateHaskell    #-}
+
 -- | The source location annotated nix expression type and supporting types.
 --
 module Nix.Expr.Types.Annotated
@@ -18,7 +20,6 @@ import           Control.Monad        hiding (forM_, mapM, sequence)
 import           Data.Data
 import           Data.Fix
 import           Data.Function        (on)
-import           Data.Functor.Classes (Show1(..))
 import           Data.Functor.Compose
 import           Data.Semigroup
 import           GHC.Generics
@@ -26,6 +27,7 @@ import           Nix.Expr.Types
 import           Nix.Parser.Library   (Delta(..))
 import           Prelude              hiding (concat, concatMap, elem, foldr,
                                        mapM, minimum, readFile, sequence)
+import           Text.Show.Deriving
 
 -- | A location in a source file
 data SrcSpan = SrcSpan{ spanBegin :: Delta
@@ -42,8 +44,7 @@ data Ann ann a = Ann{ annotation :: ann
                     }
   deriving (Ord, Eq, Data, Generic, Typeable, Functor, Foldable, Traversable, Read, Show)
 
-instance Show ann => Show1 (Ann ann) where
+$(deriveShow1 ''Ann)
-  showsPrec1 = showsPrec
 
 instance Semigroup SrcSpan where
   s1 <> s2 = SrcSpan ((min `on` spanBegin) s1 s2)

default.nix

@@ -1,4 +1,4 @@
-{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc7102" }:
+{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc801" }:
 let
   haskellPackages = nixpkgs.pkgs.haskell.packages.${compiler};
 in

hnix.cabal

@@ -51,9 +51,10 @@ Library
     RankNTypes
     TupleSections
   Build-depends:
-      base                     >= 4.6          && < 5
+      base                     >= 4.9          && < 5
     , ansi-wl-pprint
     , containers
+    , deriving-compat >= 0.3 && < 0.4
     , text
     , transformers
     , parsers >= 0.10

project.nix

@@ -1,6 +1,6 @@
 { mkDerivation, ansi-wl-pprint, base, containers, data-fix, deepseq
 , parsers, stdenv, tasty, tasty-hunit, tasty-th, text, transformers
-, trifecta, unordered-containers, cabal-install, criterion, pkgs
+, trifecta, unordered-containers, criterion, pkgs, deriving-compat
 }:
 
 let
@@ -18,7 +18,7 @@ mkDerivation {
   isExecutable = true;
   libraryHaskellDepends = [
     ansi-wl-pprint base containers data-fix deepseq parsers text
-    transformers trifecta unordered-containers cabal-install criterion
+    transformers trifecta unordered-containers criterion deriving-compat
   ];
   executableHaskellDepends = [
     ansi-wl-pprint base containers data-fix deepseq

shell.nix

@@ -1,2 +1,2 @@
-{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc7103" }:
+{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc801" }:
 (import ./default.nix { inherit nixpkgs compiler; }).env