dhall-json: Add a defaultConversion for converting maps (#1579)

dhall-json/src/Dhall/JSON.hs

@@ -201,6 +201,7 @@ module Dhall.JSON (
     , omitEmpty
     , parsePreservationAndOmission
     , Conversion(..)
+    , defaultConversion
     , convertToHomogeneousMaps
     , parseConversion
     , SpecialDoubleMode(..)
@@ -646,6 +647,12 @@ data Conversion
     = NoConversion
     | Conversion { mapKey :: Text, mapValue :: Text }
 
+defaultConversion :: Conversion
+defaultConversion = Conversion
+    { mapKey = "mapKey"
+    , mapValue = "mapValue"
+    }
+
 {-| Convert association lists to homogeneous maps
 
     This converts an association list of the form:

dhall-json/src/Dhall/JSON/Yaml.hs

@@ -19,7 +19,7 @@ module Dhall.JSON.Yaml
 import Data.ByteString (ByteString)
 import Data.Monoid ((<>))
 import Data.Text (Text)
-import Dhall.JSON (Conversion(..), SpecialDoubleMode(..), codeToValue)
+import Dhall.JSON (Conversion(..), SpecialDoubleMode(..))
 import Options.Applicative (Parser)
 
 import qualified Data.Aeson
@@ -27,6 +27,7 @@ import qualified Data.Aeson.Yaml
 import qualified Data.ByteString.Lazy
 import qualified Data.Vector
 import qualified Dhall
+import qualified Dhall.JSON
 import qualified Options.Applicative
 
 data Options = Options
@@ -45,7 +46,7 @@ defaultOptions =
           , omission = id
           , documents = False
           , quoted = False
-          , conversion = NoConversion
+          , conversion = Dhall.JSON.defaultConversion
           , file = Nothing
           , output = Nothing
           }
@@ -76,7 +77,7 @@ dhallToYaml Options{..} mFilePath code = do
   
   let explaining = if explain then Dhall.detailed else id
 
-  json <- omission <$> explaining (codeToValue conversion UseYAMLEncoding mFilePath code)
+  json <- omission <$> explaining (Dhall.JSON.codeToValue conversion UseYAMLEncoding mFilePath code)
 
   return $ jsonToYaml json documents quoted
 

dhall-json/tasty/Main.hs

@@ -5,7 +5,6 @@
 module Main where
 
 import Data.Monoid ((<>))
-import Dhall.JSON (Conversion(..))
 import Test.Tasty (TestTree)
 
 import qualified Data.Aeson           as Aeson
@@ -67,12 +66,8 @@ testDhallToJSON prefix = Test.Tasty.HUnit.testCase prefix $ do
 
     _ <- Core.throws (Dhall.TypeCheck.typeOf resolvedExpression)
 
-    let mapKey     = "mapKey"
-    let mapValue   = "mapValue"
-    let conversion = Conversion {..}
-
     let convertedExpression =
-            Dhall.JSON.convertToHomogeneousMaps conversion resolvedExpression
+            Dhall.JSON.convertToHomogeneousMaps Dhall.JSON.defaultConversion resolvedExpression
 
     actualValue <- do
         Core.throws (Dhall.JSON.dhallToJSON convertedExpression)

dhall-yaml/tasty/Main.hs

@@ -10,7 +10,6 @@ import Test.Tasty (TestTree)
 
 import qualified Data.ByteString
 import qualified Data.Text.IO
-import qualified Dhall.JSON
 import qualified Dhall.JSON.Yaml
 import qualified Dhall.Yaml
 import qualified GHC.IO.Encoding
@@ -38,7 +37,6 @@ testTree =
             "./tasty/data/emptyList"
         , testDhallToYaml
             Dhall.JSON.Yaml.defaultOptions
-                { conversion = Dhall.JSON.Conversion "mapKey" "mapValue" }
             "./tasty/data/emptyMap"
         , Test.Tasty.ExpectedFailure.ignoreTestBecause "#1516" $
           testDhallToYaml