Change Generic JSON instances to TemplateHaskell (#4085)

2 files changed, 22 insertions, 51 deletions

diff --git a/src/Text/Pandoc/Extensions.hs b/src/Text/Pandoc/Extensions.hs
index b7227860a..67ad2ad04 100644
--- a/src/Text/Pandoc/Extensions.hs
+++ b/src/Text/Pandoc/Extensions.hs
@@ -15,8 +15,10 @@ You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 -}
-{-# LANGUAGE DeriveDataTypeable #-}
-{-# LANGUAGE DeriveGeneric      #-}
+{-# LANGUAGE DeriveDataTypeable         #-}
+{-# LANGUAGE DeriveGeneric              #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE TemplateHaskell            #-}
 
 {- |
    Module      : Text.Pandoc.Extensions
@@ -45,8 +47,8 @@ module Text.Pandoc.Extensions ( Extension(..)
                               , githubMarkdownExtensions
                               , multimarkdownExtensions )
 where
-import Data.Aeson (FromJSON (..), ToJSON (..), defaultOptions,
-                   genericToEncoding)
+import Data.Aeson (FromJSON (..), ToJSON (..), defaultOptions)
+import Data.Aeson.TH (deriveJSON)
 import Data.Bits (clearBit, setBit, testBit, (.|.))
 import Data.Data (Data)
 import Data.Typeable (Typeable)
@@ -55,11 +57,7 @@ import Text.Pandoc.Shared (safeRead)
 import Text.Parsec
 
 newtype Extensions = Extensions Integer
-  deriving (Show, Read, Eq, Ord, Data, Typeable, Generic)
-
-instance ToJSON Extensions where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON Extensions
+  deriving (Show, Read, Eq, Ord, Data, Typeable, Generic, ToJSON, FromJSON)
 
 instance Monoid Extensions where
   mempty = Extensions 0
@@ -156,10 +154,6 @@ data Extension =
     | Ext_amuse -- ^ Enable Text::Amuse extensions to Emacs Muse markup
     deriving (Show, Read, Enum, Eq, Ord, Bounded, Data, Typeable, Generic)
 
-instance ToJSON Extension where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON Extension
-
 -- | Extensions to be used with pandoc-flavored markdown.
 pandocExtensions :: Extensions
 pandocExtensions = extensionsFromList
@@ -373,3 +367,5 @@ parseFormatSpec = parse formatSpec ""
           return $ case polarity of
                         '-' -> disableExtension ext
                         _   -> enableExtension ext
+
+$(deriveJSON defaultOptions ''Extension)
diff --git a/src/Text/Pandoc/Options.hs b/src/Text/Pandoc/Options.hs
index 03960b6b9..1fb838321 100644
--- a/src/Text/Pandoc/Options.hs
+++ b/src/Text/Pandoc/Options.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE DeriveGeneric      #-}
+{-# LANGUAGE TemplateHaskell    #-}
 {-
 Copyright (C) 2012-2017 John MacFarlane <jgm@berkeley.edu>
 
@@ -45,8 +46,8 @@ module Text.Pandoc.Options ( module Text.Pandoc.Extensions
                            , def
                            , isEnabled
                            ) where
-import Data.Aeson (FromJSON (..), ToJSON (..), defaultOptions,
-                   genericToEncoding)
+import Data.Aeson (defaultOptions)
+import Data.Aeson.TH (deriveJSON)
 import Data.Data (Data)
 import Data.Default
 import qualified Data.Set as Set
@@ -75,10 +76,6 @@ data ReaderOptions = ReaderOptions{
 instance HasSyntaxExtensions ReaderOptions where
   getExtensions opts = readerExtensions opts
 
-instance ToJSON ReaderOptions where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON ReaderOptions
-
 instance Default ReaderOptions
   where def = ReaderOptions{
                  readerExtensions            = emptyExtensions
@@ -116,29 +113,17 @@ data HTMLMathMethod = PlainMath
                     | KaTeX String                -- url of KaTeX files
                     deriving (Show, Read, Eq, Data, Typeable, Generic)
 
-instance ToJSON HTMLMathMethod where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON HTMLMathMethod
-
 data CiteMethod = Citeproc                        -- use citeproc to render them
                   | Natbib                        -- output natbib cite commands
                   | Biblatex                      -- output biblatex cite commands
                 deriving (Show, Read, Eq, Data, Typeable, Generic)
 
-instance ToJSON CiteMethod where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON CiteMethod
-
 -- | Methods for obfuscating email addresses in HTML.
 data ObfuscationMethod = NoObfuscation
                        | ReferenceObfuscation
                        | JavascriptObfuscation
                        deriving (Show, Read, Eq, Data, Typeable, Generic)
 
-instance ToJSON ObfuscationMethod where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON ObfuscationMethod
-
 -- | Varieties of HTML slide shows.
 data HTMLSlideVariant = S5Slides
                       | SlidySlides
@@ -148,30 +133,18 @@ data HTMLSlideVariant = S5Slides
                       | NoSlides
                       deriving (Show, Read, Eq, Data, Typeable, Generic)
 
-instance ToJSON HTMLSlideVariant where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON HTMLSlideVariant
-
 -- | Options for accepting or rejecting MS Word track-changes.
 data TrackChanges = AcceptChanges
                   | RejectChanges
                   | AllChanges
                   deriving (Show, Read, Eq, Data, Typeable, Generic)
 
-instance ToJSON TrackChanges where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON TrackChanges
-
 -- | Options for wrapping text in the output.
 data WrapOption = WrapAuto        -- ^ Automatically wrap to width
                 | WrapNone        -- ^ No non-semantic newlines
                 | WrapPreserve    -- ^ Preserve wrapping of input source
                 deriving (Show, Read, Eq, Data, Typeable, Generic)
 
-instance ToJSON WrapOption where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON WrapOption
-
 -- | Options defining the type of top-level headers.
 data TopLevelDivision = TopLevelPart      -- ^ Top-level headers become parts
                       | TopLevelChapter   -- ^ Top-level headers become chapters
@@ -180,20 +153,12 @@ data TopLevelDivision = TopLevelPart      -- ^ Top-level headers become parts
                                           --   heuristics
                       deriving (Show, Read, Eq, Data, Typeable, Generic)
 
-instance ToJSON TopLevelDivision where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON TopLevelDivision
-
 -- | Locations for footnotes and references in markdown output
 data ReferenceLocation = EndOfBlock    -- ^ End of block
                        | EndOfSection  -- ^ prior to next section header (or end of document)
                        | EndOfDocument -- ^ at end of document
                        deriving (Show, Read, Eq, Data, Typeable, Generic)
 
-instance ToJSON ReferenceLocation where
-  toEncoding = genericToEncoding defaultOptions
-instance FromJSON ReferenceLocation
-
 -- | Options for writers
 data WriterOptions = WriterOptions
   { writerTemplate          :: Maybe String -- ^ Template to use
@@ -271,3 +236,13 @@ instance HasSyntaxExtensions WriterOptions where
 -- | Returns True if the given extension is enabled.
 isEnabled :: HasSyntaxExtensions a => Extension -> a -> Bool
 isEnabled ext opts = ext `extensionEnabled` getExtensions opts
+
+$(deriveJSON defaultOptions ''ReaderOptions)
+$(deriveJSON defaultOptions ''HTMLMathMethod)
+$(deriveJSON defaultOptions ''CiteMethod)
+$(deriveJSON defaultOptions ''ObfuscationMethod)
+$(deriveJSON defaultOptions ''HTMLSlideVariant)
+$(deriveJSON defaultOptions ''TrackChanges)
+$(deriveJSON defaultOptions ''WrapOption)
+$(deriveJSON defaultOptions ''TopLevelDivision)
+$(deriveJSON defaultOptions ''ReferenceLocation)