Lua modules: add function pandoc.utils.hierarchicalize

Convert list of Pandoc blocks into (hierarchical) list of Elements.

2 files changed, 39 insertions, 8 deletions

diff --git a/src/Text/Pandoc/Lua/Module/Utils.hs b/src/Text/Pandoc/Lua/Module/Utils.hs
index 458716a03..35495dae1 100644
--- a/src/Text/Pandoc/Lua/Module/Utils.hs
+++ b/src/Text/Pandoc/Lua/Module/Utils.hs
@@ -44,12 +44,24 @@ 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
@@ -86,10 +98,3 @@ instance FromLuaStack AstElement where
 -- | Convert a number < 4000 to uppercase roman numeral.
 toRomanNumeral :: LuaInteger -> Lua String
 toRomanNumeral = return . Shared.toRomanNumeral . fromIntegral
-
--- | 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
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)