Revised Text.Pandoc.Templates to accept JSON contexts.

Currently the library is set up with a shim for association
lists, for compatibility, but this can change when the writers
are changed.

New export: `varListToJSON`.

Removed `Empty`.

Simplified template type to a newtype.

2 files changed, 10 insertions, 2 deletions

diff --git a/src/Text/Pandoc/Writers/HTML.hs b/src/Text/Pandoc/Writers/HTML.hs
index 1e4b19184..1cc17d7fd 100644
--- a/src/Text/Pandoc/Writers/HTML.hs
+++ b/src/Text/Pandoc/Writers/HTML.hs
@@ -45,6 +45,7 @@ import Numeric ( showHex )
 import Data.Char ( ord, toLower )
 import Data.List ( isPrefixOf, intersperse )
 import Data.String ( fromString )
+import qualified Data.Text as T
 import Data.Maybe ( catMaybes )
 import Control.Monad.State
 import Text.Blaze.Html hiding(contents)
@@ -212,7 +213,10 @@ inTemplate opts tit auths authsMeta date toc body' newvars =
                          Nothing -> [])  ++
                     [ ("author", renderHtml a) | a <- auths ] ++
                     [ ("author-meta", stripTags $ renderHtml a) | a <- authsMeta ]
-  in  renderTemplate context $ writerTemplate opts
+      template    = case compileTemplate (T.pack $ writerTemplate opts) of
+                          Left  e -> error e
+                          Right t -> t
+  in  renderTemplate template (varListToJSON context)
 
 -- | Like Text.XHtml's identifier, but adds the writerIdentifierPrefix
 prefixedId :: WriterOptions -> String -> Attribute
diff --git a/src/Text/Pandoc/Writers/Man.hs b/src/Text/Pandoc/Writers/Man.hs
index 5541aeb3b..17be983ce 100644
--- a/src/Text/Pandoc/Writers/Man.hs
+++ b/src/Text/Pandoc/Writers/Man.hs
@@ -38,6 +38,7 @@ import Text.Printf ( printf )
 import Data.List ( isPrefixOf, intersperse, intercalate )
 import Text.Pandoc.Pretty
 import Control.Monad.State
+import qualified Data.Text as T
 
 type Notes = [[Block]]
 data WriterState = WriterState { stNotes  :: Notes
@@ -77,8 +78,11 @@ pandocToMan opts (Pandoc (Meta title authors date) blocks) = do
                  , ("description", render' description) ] ++
                  [ ("has-tables", "yes") | hasTables ] ++
                  [ ("author", render' a) | a <- authors' ]
+      template = case compileTemplate (T.pack $ writerTemplate opts) of
+                       Left  e -> error e
+                       Right t -> t
   if writerStandalone opts
-     then return $ renderTemplate context $ writerTemplate opts
+     then return $ renderTemplate template (varListToJSON context)
      else return main
 
 -- | Return man representation of notes.