support ghc 7.4 and 7.6

.travis.yml

@@ -13,13 +13,19 @@ before_cache:
 
 matrix:
   include:
-    - env: CABALVER=1.18 GHCVER=7.8.4
+    - env: CABALVER=1.16 GHCVER=7.4.2
+      compiler: ": #GHC 7.4.2"
+      addons: {apt: {packages: [cabal-install-1.16,ghc-7.4.2], sources: [hvr-ghc]}}
+    - env: CABALVER=1.16 GHCVER=7.6.3
+      compiler: ": #GHC 7.6.3"
+      addons: {apt: {packages: [cabal-install-1.16,ghc-7.6.3], sources: [hvr-ghc]}}
+    - env: CABALVER=1.18 GHCVER=7.8.4 ENABLE_BENCHMARKS=--enable-benchmarks
       compiler: ": #GHC 7.8.4"
       addons: {apt: {packages: [cabal-install-1.18,ghc-7.8.4], sources: [hvr-ghc]}}
-    - env: CABALVER=1.22 GHCVER=7.10.2
+    - env: CABALVER=1.22 GHCVER=7.10.2 ENABLE_BENCHMARKS=--enable-benchmarks
       compiler: ": #GHC 7.10.2"
       addons: {apt: {packages: [cabal-install-1.22,ghc-7.10.2], sources: [hvr-ghc]}}
-    - env: CABALVER=1.24 GHCVER=8.0.1
+    - env: CABALVER=1.24 GHCVER=8.0.1 ENABLE_BENCHMARKS=--enable-benchmarks
       compiler: ": #GHC 8.0.1"
       addons: {apt: {packages: [cabal-install-1.24,ghc-8.0.1], sources: [hvr-ghc]}}
 
@@ -37,7 +43,7 @@ install:
    fi
  - travis_retry cabal update -v
  - sed -i 's/^jobs:/-- jobs:/' ${HOME}/.cabal/config
- - cabal install --only-dependencies --enable-tests --enable-benchmarks --dry -v > installplan.txt
+ - cabal install --only-dependencies --enable-tests $ENABLE_BENCHMARKS --dry -v > installplan.txt
  - sed -i -e '1,/^Resolving /d' installplan.txt; cat installplan.txt
 
 # check whether current requested install-plan matches cached package-db snapshot
@@ -51,7 +57,7 @@ install:
      echo "cabal build-cache MISS";
      rm -rf $HOME/.cabsnap;
      mkdir -p $HOME/.ghc $HOME/.cabal/lib $HOME/.cabal/share $HOME/.cabal/bin;
-     cabal install --only-dependencies --enable-tests --enable-benchmarks;
+     cabal install --only-dependencies --enable-tests $ENABLE_BENCHMARKS;
    fi
 
 # snapshot package-db on cache miss
@@ -67,7 +73,7 @@ install:
 # any command which exits with a non-zero exit code causes the build to fail.
 script:
  - if [ -f configure.ac ]; then autoreconf -i; fi
- - cabal configure --enable-tests --enable-benchmarks -v2  # -v2 provides useful information for debugging
+ - cabal configure --enable-tests $ENABLE_BENCHMARKS -v2  # -v2 provides useful information for debugging
  - cabal build   # this builds all libraries and executables (including tests/benchmarks)
  - cabal test
  - cabal check

aeson-quick.cabal

@@ -1,7 +1,7 @@
 Name:              aeson-quick
 Version:           0.1.1.1
 Build-Type:        Simple
-Cabal-Version:     >= 1.10
+Cabal-Version:     >= 1.16
 License:           BSD3
 License-File:      LICENSE
 Author:            Scott Sadler
@@ -12,7 +12,7 @@ Synopsis:          Quick JSON extractions with Aeson
 Description:       DSL on top of Aeson. This library is /experimental/.
 Copyright:         (c) 2014-2017 Scott Sadler
 Stability:         Experimental
-Tested-With:       GHC == 7.8.4, GHC == 7.10.2, GHC == 8.0.1
+Tested-With:       GHC == 7.4.2, GHC == 7.6.3, GHC == 7.8.4, GHC == 7.10.2, GHC == 8.0.1
 
 
 Library
@@ -25,6 +25,8 @@ Library
                     , text                  >= 1.2    && <  1.3
                     , unordered-containers  >= 0.2.5  && <  0.3
                     , vector                >= 0.10   && <  0.12
+  if impl(ghc < 7.5)
+    Build-Depends:    ghc-prim              >= 0.2
   default-language: Haskell2010
 
 test-suite aeson-quick-test
@@ -55,6 +57,7 @@ benchmark benchmark
                     , text                  >= 1.2    && <  1.3
   default-language: Haskell2010
 
+
 source-repository head
   type:     git
   location: https://github.com/libscott/aeson-quick

test/Test.hs

@@ -5,7 +5,6 @@ import Control.Applicative
 
 import Data.Aeson.Quick
 import Data.ByteString.Lazy (ByteString)
-import Data.Either
 
 import Lens.Micro
 
@@ -160,3 +159,7 @@ d s = case decode s of
            Just v -> v
            Nothing -> error $ "Coult not decode JSON: " ++ show s
 
+
+isLeft :: Either a b -> Bool
+isLeft e = case e of Left _ -> True
+                     _      -> False