Change JSON encodings of some types.

- For LineEnding use lowercase constructors, e.g. `crlf`, `native`.
  This was the original intent, but there was a bug in the
  implementation.
- For HTMLSlideVariant use lowercase constructors.
- For ReaderOptions use e.g. `default-image-extension`
  instead of `readerDefaultImageExtension` for field names.
- For Extension, use e.g. `tex_math_dollars` instead of
  `Ext_tex_math_dollars` as constructor.
- For Extensions, use an array of Extensions, instead of
  an object wrapping the tag `Extensions` and an integer.
  (The representation is not supposed to be part of the
  public API.)
- For Opt, use field names like `tab-stop` instead of `optTabStop`.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/Text/Pandoc/Options.hs b/src/Text/Pandoc/Options.hs
index ba18377c2..6a3028b14 100644
--- a/src/Text/Pandoc/Options.hs
+++ b/src/Text/Pandoc/Options.hs
@@ -37,6 +37,7 @@ import Control.Applicative ((<|>))
 import Data.Maybe (fromMaybe)
 import Data.Data (Data)
 import Data.Default
+import Data.Char (toLower)
 import Data.Text (Text)
 import qualified Data.Set as Set
 import Data.Typeable (Typeable)
@@ -371,6 +372,9 @@ defaultKaTeXURL :: Text
 defaultKaTeXURL = "https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.11.1/"
 
 -- Update documentation in doc/filters.md if this is changed.
-$(deriveJSON defaultOptions ''ReaderOptions)
+$(deriveJSON defaultOptions{ fieldLabelModifier =
+                               camelTo2 '-' . drop 6 }
+                            ''ReaderOptions)
 
-$(deriveJSON defaultOptions ''HTMLSlideVariant)
+$(deriveJSON defaultOptions{ constructorTagModifier = map toLower }
+  ''HTMLSlideVariant)