module CMarkGFM (
    commonmarkToHtml
  , commonmarkToXml
  , commonmarkToMan
  , commonmarkToLaTeX
  , commonmarkToNode
  , nodeToHtml
  , nodeToXml
  , nodeToMan
  , nodeToLaTeX
  , nodeToCommonmark
  , optSourcePos
  , optHardBreaks
  , optSmart
  , optSafe
  , extStrikethrough
  , extTable
  , extAutolink
  , extTagfilter
  , Node(..)
  , NodeType(..)
  , PosInfo(..)
  , DelimType(..)
  , ListType(..)
  , ListAttributes(..)
  , Url
  , Title
  , Level
  , Info
  , TableCellAlignment(..)
  , CMarkOption
  , CMarkExtension
  ) where
import Foreign
import Foreign.C.Types
import Foreign.C.String (CString, withCString)
import qualified System.IO.Unsafe as Unsafe
import Data.Maybe (fromMaybe)
import GHC.Generics (Generic)
import Data.Data (Data)
import Data.Typeable (Typeable)
import Data.Text (Text, empty)
import qualified Data.Text.Foreign as TF
import qualified Data.ByteString as B
import Data.Text.Encoding (encodeUtf8)
import Control.Applicative ((<$>), (<*>))
ensurePluginsRegistered :: IO ()
ensurePluginsRegistered = c_core_extensions_ensure_registered
freeLlist :: LlistPtr a -> IO ()
freeLlist = c_cmark_llist_free c_CMARK_DEFAULT_MEM_ALLOCATOR
extsToLlist :: [ExtensionPtr] -> IO (LlistPtr ExtensionPtr)
extsToLlist [] = return nullPtr
extsToLlist (h:t) = do
  t' <- extsToLlist t
  c_cmark_llist_append c_CMARK_DEFAULT_MEM_ALLOCATOR t' (castPtr h)
resolveExts :: [CMarkExtension] -> IO [ExtensionPtr]
resolveExts exts = do
  ensurePluginsRegistered
  mapM resolveExt exts
  where resolveExt ext = do p <- withCString (unCMarkExtension ext) c_cmark_find_syntax_extension
                            if p == nullPtr then
                              fail $ "could not load extension " ++ unCMarkExtension ext
                            else
                              return p
commonmarkToHtml :: [CMarkOption] -> [CMarkExtension] -> Text -> Text
commonmarkToHtml opts exts =
  commonmarkToX render_html opts exts Nothing
  where exts' = Unsafe.unsafePerformIO $ resolveExts exts
        render_html n o _ = do
          llist <- extsToLlist exts'
          r <- c_cmark_render_html n o llist
          freeLlist llist
          return r
commonmarkToXml :: [CMarkOption] -> [CMarkExtension] -> Text -> Text
commonmarkToXml opts exts = commonmarkToX render_xml opts exts Nothing
  where render_xml n o _ = c_cmark_render_xml n o
commonmarkToMan :: [CMarkOption] -> [CMarkExtension] -> Maybe Int -> Text -> Text
commonmarkToMan = commonmarkToX c_cmark_render_man
commonmarkToLaTeX :: [CMarkOption] -> [CMarkExtension] -> Maybe Int -> Text -> Text
commonmarkToLaTeX = commonmarkToX c_cmark_render_latex
commonmarkToNode :: [CMarkOption] -> [CMarkExtension] -> Text -> Node
commonmarkToNode opts exts s = Unsafe.unsafePerformIO $ do
  exts' <- resolveExts exts
  parser <- c_cmark_parser_new (combineOptions opts)
  mapM_ (c_cmark_parser_attach_syntax_extension parser) exts'
  TF.withCStringLen s $! \(ptr, len) ->
             c_cmark_parser_feed parser ptr len
  nptr <- c_cmark_parser_finish parser
  c_cmark_parser_free parser
  fptr <- newForeignPtr c_cmark_node_free nptr
  withForeignPtr fptr toNode
nodeToHtml :: [CMarkOption] -> [CMarkExtension] -> Node -> Text
nodeToHtml opts exts =
  nodeToX render_html opts Nothing
  where exts' = Unsafe.unsafePerformIO $ resolveExts exts
        render_html n o _ = do
          llist <- extsToLlist exts'
          r <- c_cmark_render_html n o llist
          freeLlist llist
          return r
nodeToXml :: [CMarkOption] -> Node -> Text
nodeToXml opts = nodeToX render_xml opts Nothing
  where render_xml n o _ = c_cmark_render_xml n o
nodeToMan :: [CMarkOption] -> Maybe Int -> Node -> Text
nodeToMan = nodeToX c_cmark_render_man
nodeToLaTeX :: [CMarkOption] -> Maybe Int -> Node -> Text
nodeToLaTeX = nodeToX c_cmark_render_latex
nodeToCommonmark :: [CMarkOption] -> Maybe Int -> Node -> Text
nodeToCommonmark = nodeToX c_cmark_render_commonmark
type Renderer = NodePtr -> CInt -> Int -> IO CString
nodeToX :: Renderer -> [CMarkOption] -> Maybe Int -> Node -> Text
nodeToX renderer opts mbWidth node = Unsafe.unsafePerformIO $ do
  nptr <- fromNode node
  fptr <- newForeignPtr c_cmark_node_free nptr
  withForeignPtr fptr $ \ptr -> do
    cstr <- renderer ptr (combineOptions opts) (fromMaybe 0 mbWidth)
    TF.peekCStringLen (cstr, c_strlen cstr)
commonmarkToX :: Renderer
              -> [CMarkOption]
              -> [CMarkExtension]
              -> Maybe Int
              -> Text
              -> Text
commonmarkToX renderer opts exts mbWidth s = Unsafe.unsafePerformIO $
  TF.withCStringLen s $ \(ptr, len) -> do
    let opts' = combineOptions opts
    exts' <- resolveExts exts
    parser <- c_cmark_parser_new opts'
    mapM_ (c_cmark_parser_attach_syntax_extension parser) exts'
    c_cmark_parser_feed parser ptr len
    nptr <- c_cmark_parser_finish parser
    c_cmark_parser_free parser
    fptr <- newForeignPtr c_cmark_node_free nptr
    withForeignPtr fptr $ \p -> do
      str <- renderer p opts' (fromMaybe 0 mbWidth)
      t <- TF.peekCStringLen $! (str, c_strlen str)
      return t
data ParserPhantom
type ParserPtr = Ptr ParserPhantom
data NodePhantom
type NodePtr = Ptr NodePhantom
data LlistPhantom a
type LlistPtr a = Ptr (LlistPhantom a)
data MemPhantom
type MemPtr = Ptr MemPhantom
data ExtensionPhantom
type ExtensionPtr = Ptr ExtensionPhantom
data Node = Node (Maybe PosInfo) NodeType [Node]
     deriving (Show, Read, Eq, Ord, Typeable, Data, Generic)
data DelimType =
    PERIOD_DELIM
  | PAREN_DELIM
  deriving (Show, Read, Eq, Ord, Typeable, Data, Generic)
data ListType =
    BULLET_LIST
  | ORDERED_LIST
  deriving (Show, Read, Eq, Ord, Typeable, Data, Generic)
data ListAttributes = ListAttributes{
    listType     :: ListType
  , listTight    :: Bool
  , listStart    :: Int
  , listDelim    :: DelimType
  } deriving (Show, Read, Eq, Ord, Typeable, Data, Generic)
type Url = Text
type Title = Text
type Level = Int
type Info = Text
type OnEnter = Text
type OnExit = Text
data TableCellAlignment = NoAlignment | LeftAligned | CenterAligned | RightAligned
     deriving (Show, Read, Eq, Ord, Typeable, Data, Generic)
data NodeType =
    DOCUMENT
  | THEMATIC_BREAK
  | PARAGRAPH
  | BLOCK_QUOTE
  | HTML_BLOCK Text
  | CUSTOM_BLOCK OnEnter OnExit
  | CODE_BLOCK Info Text
  | HEADING Level
  | LIST ListAttributes
  | ITEM
  | TEXT Text
  | SOFTBREAK
  | LINEBREAK
  | HTML_INLINE Text
  | CUSTOM_INLINE OnEnter OnExit
  | CODE Text
  | EMPH
  | STRONG
  | LINK Url Title
  | IMAGE Url Title
  | STRIKETHROUGH
  | TABLE [TableCellAlignment]
  | TABLE_ROW
  | TABLE_CELL
  deriving (Show, Read, Eq, Ord, Typeable, Data, Generic)
data PosInfo = PosInfo{ startLine   :: Int
                      , startColumn :: Int
                      , endLine     :: Int
                      , endColumn   :: Int
                      }
  deriving (Show, Read, Eq, Ord, Typeable, Data, Generic)
newtype CMarkOption = CMarkOption { unCMarkOption :: CInt }
combineOptions :: [CMarkOption] -> CInt
combineOptions = foldr ((.|.) . unCMarkOption) 0
optSourcePos :: CMarkOption
optSourcePos = CMarkOption 2
optHardBreaks :: CMarkOption
optHardBreaks = CMarkOption 4
optSmart :: CMarkOption
optSmart = CMarkOption 1024
optSafe :: CMarkOption
optSafe = CMarkOption 8
newtype CMarkExtension = CMarkExtension { unCMarkExtension :: String }
extStrikethrough :: CMarkExtension
extStrikethrough = CMarkExtension "strikethrough"
extTable :: CMarkExtension
extTable = CMarkExtension "table"
extAutolink :: CMarkExtension
extAutolink = CMarkExtension "autolink"
extTagfilter :: CMarkExtension
extTagfilter = CMarkExtension "tagfilter"
ptrToNodeType :: NodePtr -> IO NodeType
ptrToNodeType ptr = do
  nodeType <- c_cmark_node_get_type ptr
  case nodeType of
       32769
         -> return DOCUMENT
       32778
         -> return THEMATIC_BREAK
       32776
         -> return PARAGRAPH
       32770
         -> return BLOCK_QUOTE
       32774
         -> HTML_BLOCK <$> literal
       32775
         -> CUSTOM_BLOCK <$> onEnter <*> onExit
       32773
         -> CODE_BLOCK <$> info
                       <*> literal
       32771
         -> LIST <$> listAttr
       32772
         -> return ITEM
       32777
         -> HEADING <$> level
       49159
         -> return EMPH
       49160
         -> return STRONG
       49161
         -> LINK <$> url <*> title
       49162
         -> IMAGE <$> url <*> title
       49153
         -> TEXT <$> literal
       49156
         -> CODE <$> literal
       49157
         -> HTML_INLINE <$> literal
       49158
         -> CUSTOM_INLINE <$> onEnter <*> onExit
       49154
         -> return SOFTBREAK
       49155
         -> return LINEBREAK
       _ -> if nodeType == fromIntegral (Unsafe.unsafePerformIO $ peek c_CMARK_NODE_STRIKETHROUGH) then
              return STRIKETHROUGH
            else if nodeType == fromIntegral (Unsafe.unsafePerformIO $ peek c_CMARK_NODE_TABLE) then
              TABLE <$> alignments
            else if nodeType == fromIntegral (Unsafe.unsafePerformIO $ peek c_CMARK_NODE_TABLE_ROW) then
              return TABLE_ROW
            else if nodeType == fromIntegral (Unsafe.unsafePerformIO $ peek c_CMARK_NODE_TABLE_CELL) then
              return TABLE_CELL
            else
              error $ "Unknown node type " ++ (show nodeType)
  where literal   = c_cmark_node_get_literal ptr >>= totext
        level     = c_cmark_node_get_heading_level ptr
        onEnter    = c_cmark_node_get_on_enter ptr >>= totext
        onExit     = c_cmark_node_get_on_exit  ptr >>= totext
        listAttr  = do
          listtype <- c_cmark_node_get_list_type ptr
          listdelim <- c_cmark_node_get_list_delim ptr
          tight <- c_cmark_node_get_list_tight ptr
          start <- c_cmark_node_get_list_start ptr
          return ListAttributes{
            listType  = case listtype of
                             (2) -> ORDERED_LIST
                             (1)  -> BULLET_LIST
                             _                           -> BULLET_LIST
          , listDelim  = case listdelim of
                             (1) -> PERIOD_DELIM
                             (2)  -> PAREN_DELIM
                             _                           -> PERIOD_DELIM
          , listTight  = tight
          , listStart  = start
          }
        url       = c_cmark_node_get_url ptr >>= totext
        title     = c_cmark_node_get_title ptr >>= totext
        info      = c_cmark_node_get_fence_info ptr >>= totext
        alignments = do
          ncols <- c_cmarkextensions_get_table_columns ptr
          cols <- c_cmarkextensions_get_table_alignments ptr
          mapM (fmap ucharToAlignment . peekElemOff cols) [0..(fromIntegral ncols)  1]
        ucharToAlignment (CUChar 108) = LeftAligned
        ucharToAlignment (CUChar 99)  = CenterAligned
        ucharToAlignment (CUChar 114) = RightAligned
        ucharToAlignment _            = NoAlignment
getPosInfo :: NodePtr -> IO (Maybe PosInfo)
getPosInfo ptr = do
  startline <- c_cmark_node_get_start_line ptr
  endline <- c_cmark_node_get_end_line ptr
  startcol <- c_cmark_node_get_start_column ptr
  endcol <- c_cmark_node_get_end_column ptr
  if startline + endline + startcol + endcol == 0
     then return Nothing
     else return $ Just PosInfo{ startLine = startline
                               , startColumn = startcol
                               , endLine = endline
                               , endColumn = endcol }
toNode :: NodePtr -> IO Node
toNode ptr = do
  let handleNodes ptr' =
        if ptr' == nullPtr
           then return []
           else do
              x  <- toNode ptr'
              xs <- c_cmark_node_next ptr' >>= handleNodes
              return $! (x:xs)
  nodeType <- ptrToNodeType ptr
  children <- c_cmark_node_first_child ptr >>= handleNodes
  posinfo <- getPosInfo ptr
  return $! Node posinfo nodeType children
fromNode :: Node -> IO NodePtr
fromNode (Node _ nodeType children) = do
  node <- case nodeType of
            DOCUMENT    -> c_cmark_node_new (32769)
            THEMATIC_BREAK -> c_cmark_node_new (32778)
            PARAGRAPH   -> c_cmark_node_new (32776)
            BLOCK_QUOTE -> c_cmark_node_new (32770)
            HTML_BLOCK literal -> do
                     n <- c_cmark_node_new (32774)
                     c_cmark_node_set_literal n =<< fromtext literal
                     return n
            CUSTOM_BLOCK onEnter onExit -> do
                     n <- c_cmark_node_new (32775)
                     c_cmark_node_set_on_enter n =<< fromtext onEnter
                     c_cmark_node_set_on_exit  n =<< fromtext onExit
                     return n
            CODE_BLOCK info literal -> do
                     n <- c_cmark_node_new (32773)
                     c_cmark_node_set_literal n =<< fromtext literal
                     c_cmark_node_set_fence_info n =<< fromtext info
                     return n
            LIST attr   -> do
                     n <- c_cmark_node_new (32771)
                     c_cmark_node_set_list_type n $ case listType attr of
                         ORDERED_LIST -> 2
                         BULLET_LIST  -> 1
                     c_cmark_node_set_list_delim n $ case listDelim attr of
                         PERIOD_DELIM -> 1
                         PAREN_DELIM  -> 2
                     c_cmark_node_set_list_tight n $ listTight attr
                     c_cmark_node_set_list_start n $ listStart attr
                     return n
            ITEM        -> c_cmark_node_new (32772)
            HEADING lev  -> do
                     n <- c_cmark_node_new (32777)
                     c_cmark_node_set_heading_level n lev
                     return n
            EMPH        -> c_cmark_node_new (49159)
            STRONG      -> c_cmark_node_new (49160)
            LINK url title -> do
                     n <- c_cmark_node_new (49161)
                     c_cmark_node_set_url n =<< fromtext url
                     c_cmark_node_set_title n =<< fromtext title
                     return n
            IMAGE url title -> do
                     n <- c_cmark_node_new (49162)
                     c_cmark_node_set_url n =<< fromtext url
                     c_cmark_node_set_title n =<< fromtext title
                     return n
            TEXT literal -> do
                     n <- c_cmark_node_new (49153)
                     c_cmark_node_set_literal n =<< fromtext literal
                     return n
            CODE literal -> do
                     n <- c_cmark_node_new (49156)
                     c_cmark_node_set_literal n =<< fromtext literal
                     return n
            HTML_INLINE literal -> do
                     n <- c_cmark_node_new (49157)
                     c_cmark_node_set_literal n =<< fromtext literal
                     return n
            CUSTOM_INLINE onEnter onExit -> do
                     n <- c_cmark_node_new (49158)
                     c_cmark_node_set_on_enter n =<< fromtext onEnter
                     c_cmark_node_set_on_exit  n =<< fromtext onExit
                     return n
            SOFTBREAK   -> c_cmark_node_new (49154)
            LINEBREAK   -> c_cmark_node_new (49155)
            STRIKETHROUGH -> c_cmark_node_new (fromIntegral . Unsafe.unsafePerformIO $ peek c_CMARK_NODE_STRIKETHROUGH)
            TABLE _       -> error "constructing table not supported"
            TABLE_ROW     -> error "constructing table row not supported"
            TABLE_CELL    -> error "constructing table cell not supported"
  mapM_ (\child -> fromNode child >>= c_cmark_node_append_child node) children
  return node
totext :: CString -> IO Text
totext str
  | str == nullPtr = return empty
  | otherwise      = TF.peekCStringLen (str, c_strlen str)
fromtext :: Text -> IO CString
fromtext t = B.useAsCString (encodeUtf8 t) return
foreign import ccall "string.h strlen"
    c_strlen :: CString -> Int
foreign import ccall "cmark.h cmark_node_new"
    c_cmark_node_new :: Int -> IO NodePtr
foreign import ccall "cmark.h cmark_render_html"
    c_cmark_render_html :: NodePtr -> CInt -> LlistPtr ExtensionPtr -> IO CString
foreign import ccall "cmark.h cmark_render_xml"
    c_cmark_render_xml :: NodePtr -> CInt -> IO CString
foreign import ccall "cmark.h cmark_render_man"
    c_cmark_render_man :: NodePtr -> CInt -> Int -> IO CString
foreign import ccall "cmark.h cmark_render_latex"
    c_cmark_render_latex :: NodePtr -> CInt -> Int -> IO CString
foreign import ccall "cmark.h cmark_render_commonmark"
    c_cmark_render_commonmark :: NodePtr -> CInt -> Int -> IO CString
foreign import ccall "cmark.h cmark_parser_new"
    c_cmark_parser_new :: CInt -> IO ParserPtr
foreign import ccall "cmark.h cmark_parser_feed"
    c_cmark_parser_feed :: ParserPtr -> CString -> Int -> IO ()
foreign import ccall "cmark.h cmark_parser_finish"
    c_cmark_parser_finish :: ParserPtr -> IO NodePtr
foreign import ccall "cmark.h cmark_parser_free"
    c_cmark_parser_free :: ParserPtr -> IO ()
foreign import ccall "cmark.h cmark_node_get_type"
    c_cmark_node_get_type :: NodePtr -> IO Int
foreign import ccall "cmark.h cmark_node_first_child"
    c_cmark_node_first_child :: NodePtr -> IO NodePtr
foreign import ccall "cmark.h cmark_node_next"
    c_cmark_node_next :: NodePtr -> IO NodePtr
foreign import ccall "cmark.h cmark_node_get_literal"
    c_cmark_node_get_literal :: NodePtr -> IO CString
foreign import ccall "cmark.h cmark_node_get_url"
    c_cmark_node_get_url :: NodePtr -> IO CString
foreign import ccall "cmark.h cmark_node_get_title"
    c_cmark_node_get_title :: NodePtr -> IO CString
foreign import ccall "cmark.h cmark_node_get_heading_level"
    c_cmark_node_get_heading_level :: NodePtr -> IO Int
foreign import ccall "cmark.h cmark_node_get_list_type"
    c_cmark_node_get_list_type :: NodePtr -> IO Int
foreign import ccall "cmark.h cmark_node_get_list_tight"
    c_cmark_node_get_list_tight :: NodePtr -> IO Bool
foreign import ccall "cmark.h cmark_node_get_list_start"
    c_cmark_node_get_list_start :: NodePtr -> IO Int
foreign import ccall "cmark.h cmark_node_get_list_delim"
    c_cmark_node_get_list_delim :: NodePtr -> IO Int
foreign import ccall "cmark.h cmark_node_get_fence_info"
    c_cmark_node_get_fence_info :: NodePtr -> IO CString
foreign import ccall "cmark.h cmark_node_get_start_line"
    c_cmark_node_get_start_line :: NodePtr -> IO Int
foreign import ccall "cmark.h cmark_node_get_start_column"
    c_cmark_node_get_start_column :: NodePtr -> IO Int
foreign import ccall "cmark.h cmark_node_get_end_line"
    c_cmark_node_get_end_line :: NodePtr -> IO Int
foreign import ccall "cmark.h cmark_node_get_end_column"
    c_cmark_node_get_end_column :: NodePtr -> IO Int
foreign import ccall "cmark.h cmark_node_get_on_enter"
    c_cmark_node_get_on_enter :: NodePtr -> IO CString
foreign import ccall "cmark.h cmark_node_get_on_exit"
    c_cmark_node_get_on_exit :: NodePtr -> IO CString
foreign import ccall "cmark.h cmark_node_append_child"
    c_cmark_node_append_child :: NodePtr -> NodePtr -> IO Int
foreign import ccall "cmark.h cmark_node_set_literal"
    c_cmark_node_set_literal :: NodePtr -> CString -> IO Int
foreign import ccall "cmark.h cmark_node_set_url"
    c_cmark_node_set_url :: NodePtr -> CString -> IO Int
foreign import ccall "cmark.h cmark_node_set_title"
    c_cmark_node_set_title :: NodePtr -> CString -> IO Int
foreign import ccall "cmark.h cmark_node_set_heading_level"
    c_cmark_node_set_heading_level :: NodePtr -> Int -> IO Int
foreign import ccall "cmark.h cmark_node_set_list_type"
    c_cmark_node_set_list_type :: NodePtr -> Int -> IO Int
foreign import ccall "cmark.h cmark_node_set_list_tight"
    c_cmark_node_set_list_tight :: NodePtr -> Bool -> IO Int
foreign import ccall "cmark.h cmark_node_set_list_start"
    c_cmark_node_set_list_start :: NodePtr -> Int -> IO Int
foreign import ccall "cmark.h cmark_node_set_list_delim"
    c_cmark_node_set_list_delim :: NodePtr -> Int -> IO Int
foreign import ccall "cmark.h cmark_node_set_fence_info"
    c_cmark_node_set_fence_info :: NodePtr -> CString -> IO Int
foreign import ccall "cmark.h cmark_node_set_on_enter"
    c_cmark_node_set_on_enter :: NodePtr -> CString -> IO Int
foreign import ccall "cmark.h cmark_node_set_on_exit"
    c_cmark_node_set_on_exit :: NodePtr -> CString -> IO Int
foreign import ccall "cmark.h &cmark_node_free"
    c_cmark_node_free :: FunPtr (NodePtr -> IO ())
foreign import ccall "core-extensions.h core_extensions_ensure_registered"
    c_core_extensions_ensure_registered :: IO ()
foreign import ccall "cmark_extension_api.h cmark_find_syntax_extension"
    c_cmark_find_syntax_extension :: CString -> IO ExtensionPtr
foreign import ccall "cmark.h cmark_llist_append"
    c_cmark_llist_append :: MemPtr -> LlistPtr a -> Ptr () -> IO (LlistPtr a)
foreign import ccall "cmark.h cmark_llist_free"
    c_cmark_llist_free :: MemPtr -> LlistPtr a -> IO ()
foreign import ccall "cmark.h &CMARK_DEFAULT_MEM_ALLOCATOR"
    c_CMARK_DEFAULT_MEM_ALLOCATOR :: MemPtr
foreign import ccall "cmark_extension_api.h cmark_parser_attach_syntax_extension"
    c_cmark_parser_attach_syntax_extension :: ParserPtr -> ExtensionPtr -> IO ()
foreign import ccall "strikethrough.h &CMARK_NODE_STRIKETHROUGH"
    c_CMARK_NODE_STRIKETHROUGH :: Ptr CUShort
foreign import ccall "table.h &CMARK_NODE_TABLE"
    c_CMARK_NODE_TABLE :: Ptr CUShort
foreign import ccall "table.h &CMARK_NODE_TABLE_ROW"
    c_CMARK_NODE_TABLE_ROW :: Ptr CUShort
foreign import ccall "table.h &CMARK_NODE_TABLE_CELL"
    c_CMARK_NODE_TABLE_CELL :: Ptr CUShort
foreign import ccall "core-extensions.h cmarkextensions_get_table_columns"
    c_cmarkextensions_get_table_columns :: NodePtr -> IO CUShort
foreign import ccall "core-extensions.h cmarkextensions_get_table_alignments"
    c_cmarkextensions_get_table_alignments :: NodePtr -> IO (Ptr CUChar)