3 files changed, 54 insertions, 3 deletions
diff --git a/src/Text/Pandoc/Lua/Module/Utils.hs b/src/Text/Pandoc/Lua/Module/Utils.hs
index 3a3727355..35495dae1 100644
--- a/src/Text/Pandoc/Lua/Module/Utils.hs
+++ b/src/Text/Pandoc/Lua/Module/Utils.hs
@@ -30,10 +30,10 @@ module Text.Pandoc.Lua.Module.Utils
   ) where
 
 import Control.Applicative ((<|>))
-import Foreign.Lua (FromLuaStack, Lua, NumResults)
+import Foreign.Lua (FromLuaStack, Lua, LuaInteger, NumResults)
 import Text.Pandoc.Definition (Pandoc, Meta, Block, Inline)
 import Text.Pandoc.Lua.StackInstances ()
-import Text.Pandoc.Lua.Util (addFunction)
+import Text.Pandoc.Lua.Util (OrNil (OrNil), addFunction)
 
 import qualified Data.Digest.Pure.SHA as SHA
 import qualified Data.ByteString.Lazy as BSL
@@ -44,15 +44,32 @@ import qualified Text.Pandoc.Shared as Shared
 pushModule :: Lua NumResults
 pushModule = do
   Lua.newtable
+  addFunction "hierarchicalize" hierarchicalize
+  addFunction "normalize_date" normalizeDate
   addFunction "sha1" sha1
   addFunction "stringify" stringify
+  addFunction "to_roman_numeral" toRomanNumeral
   return 1
 
+-- | Convert list of Pandoc blocks into (hierarchical) list of Elements.
+hierarchicalize :: [Block] -> Lua [Shared.Element]
+hierarchicalize = return . Shared.hierarchicalize
+
+-- | Parse a date and convert (if possible) to "YYYY-MM-DD" format. We
+-- limit years to the range 1601-9999 (ISO 8601 accepts greater than
+-- or equal to 1583, but MS Word only accepts dates starting 1601).
+-- Returns nil instead of a string if the conversion failed.
+normalizeDate :: String -> Lua (OrNil String)
+normalizeDate = return . OrNil . Shared.normalizeDate
+
 -- | Calculate the hash of the given contents.
 sha1 :: BSL.ByteString
      -> Lua String
 sha1 = return . SHA.showDigest . SHA.sha1
 
+-- | Convert pandoc structure to a string with formatting removed.
+-- Footnotes are skipped (since we don't want their contents in link
+-- labels).
 stringify :: AstElement -> Lua String
 stringify el = return $ case el of
   PandocElement pd -> Shared.stringify pd
@@ -77,3 +94,7 @@ instance FromLuaStack AstElement where
       Right x -> return x
       Left _ -> Lua.throwLuaError
         "Expected an AST element, but could not parse value as such."
+
+-- | Convert a number < 4000 to uppercase roman numeral.
+toRomanNumeral :: LuaInteger -> Lua String
+toRomanNumeral = return . Shared.toRomanNumeral . fromIntegral
diff --git a/src/Text/Pandoc/Lua/StackInstances.hs b/src/Text/Pandoc/Lua/StackInstances.hs
index ce6dbdb98..119946b78 100644
--- a/src/Text/Pandoc/Lua/StackInstances.hs
+++ b/src/Text/Pandoc/Lua/StackInstances.hs
@@ -33,13 +33,15 @@ StackValue instances for pandoc types.
 module Text.Pandoc.Lua.StackInstances () where
 
 import Control.Applicative ((<|>))
+import Control.Monad (when)
 import Foreign.Lua (FromLuaStack (peek), Lua, LuaInteger, LuaNumber, StackIndex,
                     ToLuaStack (push), Type (..), throwLuaError, tryLua)
 import Text.Pandoc.Definition
 import Text.Pandoc.Lua.Util (adjustIndexBy, getTable, pushViaConstructor)
-import Text.Pandoc.Shared (safeRead)
+import Text.Pandoc.Shared (Element (Blk, Sec), safeRead)
 
 import qualified Foreign.Lua as Lua
+import qualified Text.Pandoc.Lua.Util as LuaUtil
 
 instance ToLuaStack Pandoc where
   push (Pandoc meta blocks) =
@@ -306,3 +308,27 @@ instance ToLuaStack LuaAttr where
 
 instance FromLuaStack LuaAttr where
   peek idx = LuaAttr <$> peek idx
+
+--
+-- Hierarchical elements
+--
+instance ToLuaStack Element where
+  push (Blk blk) = push blk
+  push (Sec lvl num attr label contents) = do
+    Lua.newtable
+    LuaUtil.addValue "level" lvl
+    LuaUtil.addValue "numbering" num
+    LuaUtil.addValue "attr" (LuaAttr attr)
+    LuaUtil.addValue "label" label
+    LuaUtil.addValue "contents" contents
+    pushSecMetaTable
+    Lua.setmetatable (-2)
+      where
+        pushSecMetaTable :: Lua ()
+        pushSecMetaTable = do
+          inexistant <- Lua.newmetatable "PandocElementSec"
+          when inexistant $ do
+            LuaUtil.addValue "t" "Sec"
+            Lua.push "__index"
+            Lua.pushvalue (-2)
+            Lua.rawset (-3)
diff --git a/src/Text/Pandoc/Lua/Util.hs b/src/Text/Pandoc/Lua/Util.hs
index 28d09d339..1f7664fc0 100644
--- a/src/Text/Pandoc/Lua/Util.hs
+++ b/src/Text/Pandoc/Lua/Util.hs
@@ -125,6 +125,10 @@ instance FromLuaStack a => FromLuaStack (OrNil a) where
       then return (OrNil Nothing)
       else OrNil . Just <$> Lua.peek idx
 
+instance ToLuaStack a => ToLuaStack (OrNil a) where
+  push (OrNil Nothing)  = Lua.pushnil
+  push (OrNil (Just x)) = Lua.push x
+
 -- | Helper class for pushing a single value to the stack via a lua function.
 -- See @pushViaCall@.
 class PushViaCall a where