{-# LANGUAGE OverloadedStrings   #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-
Copyright (C) 2006-2015 John MacFarlane <jgm@berkeley.edu>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-}

{- |
   Module      : Text.Pandoc.Readers.LaTeX
   Copyright   : Copyright (C) 2006-2015 John MacFarlane
   License     : GNU GPL, version 2 or above

   Maintainer  : John MacFarlane <jgm@berkeley.edu>
   Stability   : alpha
   Portability : portable

Conversion of LaTeX to 'Pandoc' document.
-}
module Text.Pandoc.Readers.LaTeX ( readLaTeX,
                                   rawLaTeXInline,
                                   rawLaTeXBlock,
                                   inlineCommand,
                                 ) where

import Control.Applicative (many, optional, (<|>))
import Control.Monad
import Control.Monad.Except (throwError)
import Data.Char (chr, isAlphaNum, isLetter, ord)
import Data.List (intercalate, isPrefixOf)
import qualified Data.Map as M
import Data.Maybe (fromMaybe, maybeToList)
import Safe (minimumDef)
import System.FilePath (addExtension, replaceExtension, takeExtension)
import Text.Pandoc.Builder
import Text.Pandoc.Class (PandocMonad, PandocPure, lookupEnv, readFileFromDirs,
                          report, setResourcePath)
import Text.Pandoc.Highlighting (fromListingsLanguage, languagesByExtension)
import Text.Pandoc.ImageSize (numUnit, showFl)
import Text.Pandoc.Logging
import Text.Pandoc.Options
import Text.Pandoc.Parsing hiding (many, mathDisplay, mathInline, optional,
                            space, (<|>))
import Text.Pandoc.Shared
import Text.Pandoc.Walk

-- | Parse LaTeX from string and return 'Pandoc' document.
readLaTeX :: PandocMonad m
          => ReaderOptions -- ^ Reader options
          -> String        -- ^ String to parse (assumes @'\n'@ line endings)
          -> m Pandoc
readLaTeX opts ltx = do
  parsed <- readWithM parseLaTeX def{ stateOptions = opts } ltx
  case parsed of
    Right result -> return result
    Left e       -> throwError e

parseLaTeX :: PandocMonad m => LP m Pandoc
parseLaTeX = do
  bs <- blocks
  eof
  st <- getState
  let meta = stateMeta st
  let doc' = doc bs
  let headerLevel (Header n _ _) = [n]
      headerLevel _ = []
  let bottomLevel = minimumDef 1 $ query headerLevel doc'
  let adjustHeaders m (Header n attr ils) = Header (n+m) attr ils
      adjustHeaders _ x = x
  let (Pandoc _ bs') =
       -- handle the case where you have \part or \chapter
       (if bottomLevel < 1
           then walk (adjustHeaders (1 - bottomLevel))
           else id) doc'
  return $ Pandoc meta bs'

type LP m = ParserT String ParserState m

anyControlSeq :: PandocMonad m => LP m String
anyControlSeq = do
  char '\\'
  next <- option '\n' anyChar
  case next of
       '\n'           -> return ""
       c | isLetter c -> (c:) <$> (many letter <* optional sp)
         | otherwise  -> return [c]

controlSeq :: PandocMonad m => String -> LP m String
controlSeq name = try $ do
  char '\\'
  case name of
        ""  -> mzero
        [c] | not (isLetter c) -> string [c]
        cs  -> string cs <* notFollowedBy letter <* optional sp
  return name

dimenarg :: PandocMonad m => LP m String
dimenarg = try $ do
  ch  <- option "" $ string "="
  num <- many1 digit
  dim <- oneOfStrings ["pt","pc","in","bp","cm","mm","dd","cc","sp"]
  return $ ch ++ num ++ dim

sp :: PandocMonad m => LP m ()
sp = whitespace <|> endline

whitespace :: PandocMonad m => LP m ()
whitespace = skipMany1 $ satisfy (\c -> c == ' ' || c == '\t')

endline :: PandocMonad m => LP m ()
endline = try (newline >> lookAhead anyChar >> notFollowedBy blankline)

isLowerHex :: Char -> Bool
isLowerHex x = x >= '0' && x <= '9' || x >= 'a' && x <= 'f'

tildeEscape :: PandocMonad m => LP m Char
tildeEscape = try $ do
  string "^^"
  c <- satisfy (\x -> x >= '\0' && x <= '\128')
  d <- if isLowerHex c
          then option "" $ count 1 (satisfy isLowerHex)
          else return ""
  if null d
     then case ord c of
           x | x >= 64 && x <= 127 -> return $ chr (x - 64)
             | otherwise           -> return $ chr (x + 64)
     else return $ chr $ read ('0':'x':c:d)

comment :: PandocMonad m => LP m ()
comment = do
  char '%'
  skipMany (satisfy (/='\n'))
  optional newline
  return ()

bgroup :: PandocMonad m => LP m ()
bgroup = try $ do
  skipMany (spaceChar <|> try (newline <* notFollowedBy blankline))
  () <$ char '{'
     <|> () <$ controlSeq "bgroup"
     <|> () <$ controlSeq "begingroup"

egroup :: PandocMonad m => LP m ()
egroup = () <$ char '}'
     <|> () <$ controlSeq "egroup"
     <|> () <$ controlSeq "endgroup"

grouped :: PandocMonad m => Monoid a => LP m a -> LP m a
grouped parser = try $ do
  bgroup
  -- first we check for an inner 'grouped', because
  -- {{a,b}} should be parsed the same as {a,b}
  try (grouped parser <* egroup)
    <|> (mconcat <$> manyTill parser egroup)

braced :: PandocMonad m => LP m String
braced = grouped chunk
  where chunk =
               many1 (satisfy (\c -> c /= '\\' && c /= '}' && c /= '{'))
           <|> try (string "\\}")
           <|> try (string "\\{")
           <|> try (string "\\\\")
           <|> ((\x -> "{" ++ x ++ "}") <$> braced)
           <|> count 1 anyChar

bracketed :: PandocMonad m => Monoid a => LP m a -> LP m a
bracketed parser = try $ char '[' *> (mconcat <$> manyTill parser (char ']'))

mathDisplay :: PandocMonad m => LP m String -> LP m Inlines
mathDisplay p = displayMath <$> (try p >>= applyMacros' . trim)

mathInline :: PandocMonad m => LP m String -> LP m Inlines
mathInline p = math <$> (try p >>= applyMacros')

mathChars :: PandocMonad m => LP m String
mathChars =
  concat <$> many (escapedChar
               <|> (snd <$> withRaw braced)
               <|> many1 (satisfy isOrdChar))
   where escapedChar = try $ do char '\\'
                                c <- anyChar
                                return ['\\',c]
         isOrdChar '$'  = False
         isOrdChar '{'  = False
         isOrdChar '}'  = False
         isOrdChar '\\' = False
         isOrdChar _    = True

quoted' :: PandocMonad m => (Inlines -> Inlines) -> LP m String -> LP m () -> LP m Inlines
quoted' f starter ender = do
  startchs <- starter
  smart <- extensionEnabled Ext_smart <$> getOption readerExtensions
  if smart
     then do
       ils <- many (notFollowedBy ender >> inline)
       (ender >> return (f (mconcat ils))) <|>
            (<> mconcat ils) <$>
                    lit (case startchs of
                              "``" -> "“"
                              "`"  -> "‘"
                              _    -> startchs)
     else lit startchs

doubleQuote :: PandocMonad m => LP m Inlines
doubleQuote = do
  quoted' doubleQuoted (try $ string "``") (void $ try $ string "''")
   <|> quoted' doubleQuoted (string "“")        (void $ char '”')
   -- the following is used by babel for localized quotes:
   <|> quoted' doubleQuoted (try $ string "\"`") (void $ try $ string "\"'")
   <|> quoted' doubleQuoted (string "\"")       (void $ char '"')

singleQuote :: PandocMonad m => LP m Inlines
singleQuote = do
  smart <- extensionEnabled Ext_smart <$> getOption readerExtensions
  if smart
     then quoted' singleQuoted (string "`") (try $ char '\'' >> notFollowedBy letter)
      <|> quoted' singleQuoted (string "‘") (try $ char '’' >> notFollowedBy letter)
     else str <$> many1 (oneOf "`\'‘’")

inline :: PandocMonad m => LP m Inlines
inline = (mempty <$ comment)
     <|> (space  <$ whitespace)
     <|> (softbreak <$ endline)
     <|> inlineText
     <|> inlineCommand
     <|> inlineEnvironment
     <|> inlineGroup
     <|> (char '-' *> option (str "-")
           (char '-' *> option (str "–") (str "—" <$ char '-')))
     <|> doubleQuote
     <|> singleQuote
     <|> (str "”" <$ try (string "''"))
     <|> (str "”" <$ char '”')
     <|> (str "’" <$ char '\'')
     <|> (str "’" <$ char '’')
     <|> (str "\160" <$ char '~')
     <|> mathDisplay (string "$$" *> mathChars <* string "$$")
     <|> mathInline  (char '$' *> mathChars <* char '$')
     <|> (guardEnabled Ext_literate_haskell *> char '|' *> doLHSverb)
     <|> (str . (:[]) <$> tildeEscape)
     <|> (do res <- oneOf "#&~^'`\"[]"
             pos <- getPosition
             report $ ParsingUnescaped [res] pos
             return $ str [res])

inlines :: PandocMonad m => LP m Inlines
inlines = mconcat <$> many (notFollowedBy (char '}') *> inline)

inlineGroup :: PandocMonad m => LP m Inlines
inlineGroup = do
  ils <- grouped inline
  if isNull ils
     then return mempty
     else return $ spanWith nullAttr ils
          -- we need the span so we can detitlecase bibtex entries;
          -- we need to know when something is {C}apitalized

block :: PandocMonad m => LP m Blocks
block = (mempty <$ comment)
    <|> (mempty <$ ((spaceChar <|> newline) *> spaces))
    <|> environment
    <|> include
    <|> macro
    <|> blockCommand
    <|> paragraph
    <|> grouped block
    <|> (mempty <$ char '&')  -- loose & in table environment


blocks :: PandocMonad m => LP m Blocks
blocks = mconcat <$> many block

getRawCommand :: PandocMonad m => String -> LP m String
getRawCommand name' = do
  rawargs <- withRaw (many (try (optional sp *> opt)) *>
                      option "" (try (optional sp *> dimenarg)) *>
                      many braced)
  return $ '\\' : name' ++ snd rawargs

lookupListDefault :: (Ord k) => v -> [k] -> M.Map k v -> v
lookupListDefault d = (fromMaybe d .) . lookupList
  where
  lookupList l m = msum $ map (`M.lookup` m) l

blockCommand :: PandocMonad m => LP m Blocks
blockCommand = try $ do
  name <- anyControlSeq
  guard $ name /= "begin" && name /= "end"
  star <- option "" (string "*" <* optional sp)
  let name' = name ++ star
  let raw = do
        rawcommand <- getRawCommand name'
        transformed <- applyMacros' rawcommand
        guard $ transformed /= rawcommand
        notFollowedBy $ parseFromString inlines transformed
        parseFromString blocks transformed
  lookupListDefault raw [name',name] blockCommands

inBrackets :: Inlines -> Inlines
inBrackets x = str "[" <> x <> str "]"

-- eat an optional argument and one or more arguments in braces
ignoreInlines :: PandocMonad m => String -> (String, LP m Inlines)
ignoreInlines name = (name, p)
  where
    p = do oa <- optargs
           let rawCommand = '\\':name ++ oa
           let doraw = guardRaw >> return (rawInline "latex" rawCommand)
           doraw <|> ignore rawCommand

guardRaw :: PandocMonad m => LP m ()
guardRaw = getOption readerExtensions >>= guard . extensionEnabled Ext_raw_tex

optargs :: PandocMonad m => LP m String
optargs = snd <$> withRaw (skipopts *> skipMany (try $ optional sp *> braced))

ignore :: (Monoid a, PandocMonad m) => String -> ParserT s u m a
ignore raw = do
  pos <- getPosition
  report $ SkippedContent raw pos
  return mempty

ignoreBlocks :: PandocMonad m => String -> (String, LP m Blocks)
ignoreBlocks name = (name, p)
  where
    p = do oa <- optargs
           let rawCommand = '\\':name ++ oa
           let doraw = guardRaw >> return (rawBlock "latex" rawCommand)
           doraw <|> ignore rawCommand

blockCommands :: PandocMonad m => M.Map String (LP m Blocks)
blockCommands = M.fromList $
  [ ("par", mempty <$ skipopts)
  , ("parbox",  braced >> grouped blocks)
  , ("title", mempty <$ (skipopts *>
                          (grouped inline >>= addMeta "title")
                      <|> (grouped block >>= addMeta "title")))
  , ("subtitle", mempty <$ (skipopts *> tok >>= addMeta "subtitle"))
  , ("author", mempty <$ (skipopts *> authors))
  -- -- in letter class, temp. store address & sig as title, author
  , ("address", mempty <$ (skipopts *> tok >>= addMeta "address"))
  , ("signature", mempty <$ (skipopts *> authors))
  , ("date", mempty <$ (skipopts *> tok >>= addMeta "date"))
  -- Koma-script metadata commands
  , ("dedication", mempty <$ (skipopts *> tok >>= addMeta "dedication"))
  -- sectioning
  , ("part", section nullAttr (-1))
  , ("part*", section nullAttr (-1))
  , ("chapter", section nullAttr 0)
  , ("chapter*", section ("",["unnumbered"],[]) 0)
  , ("section", section nullAttr 1)
  , ("section*", section ("",["unnumbered"],[]) 1)
  , ("subsection", section nullAttr 2)
  , ("subsection*", section ("",["unnumbered"],[]) 2)
  , ("subsubsection", section nullAttr 3)
  , ("subsubsection*", section ("",["unnumbered"],[]) 3)
  , ("paragraph", section nullAttr 4)
  , ("paragraph*", section ("",["unnumbered"],[]) 4)
  , ("subparagraph", section nullAttr 5)
  , ("subparagraph*", section ("",["unnumbered"],[]) 5)
  -- beamer slides
  , ("frametitle", section nullAttr 3)
  , ("framesubtitle", section nullAttr 4)
  -- letters
  , ("opening", (para . trimInlines) <$> (skipopts *> tok))
  , ("closing", skipopts *> closing)
  --
  , ("hrule", pure horizontalRule)
  , ("strut", pure mempty)
  , ("rule", skipopts *> tok *> tok *> pure horizontalRule)
  , ("item", skipopts *> looseItem)
  , ("documentclass", skipopts *> braced *> preamble)
  , ("centerline", (para . trimInlines) <$> (skipopts *> tok))
  , ("caption", skipopts *> setCaption)
  , ("bibliography", mempty <$ (skipopts *> braced >>=
                                addMeta "bibliography" . splitBibs))
  , ("addbibresource", mempty <$ (skipopts *> braced >>=
                                addMeta "bibliography" . splitBibs))
  -- includes
  , ("lstinputlisting", inputListing)
  , ("graphicspath", graphicsPath)
  -- hyperlink
  , ("hypertarget", braced >> grouped block)
  ] ++ map ignoreBlocks
  -- these commands will be ignored unless --parse-raw is specified,
  -- in which case they will appear as raw latex blocks
  [ "newcommand", "renewcommand", "newenvironment", "renewenvironment"
    -- newcommand, etc. should be parsed by macro, but we need this
    -- here so these aren't parsed as inline commands to ignore
  , "special", "pdfannot", "pdfstringdef"
  , "bibliographystyle"
  , "maketitle", "makeindex", "makeglossary"
  , "addcontentsline", "addtocontents", "addtocounter"
     -- \ignore{} is used conventionally in literate haskell for definitions
     -- that are to be processed by the compiler but not printed.
  , "ignore"
  , "hyperdef"
  , "markboth", "markright", "markleft"
  , "hspace", "vspace"
  , "newpage"
  , "clearpage"
  , "pagebreak"
  ]

graphicsPath :: PandocMonad m => LP m Blocks
graphicsPath = do
  ps <- bgroup *> (manyTill braced egroup)
  setResourcePath (".":ps)
  return mempty

addMeta :: PandocMonad m => ToMetaValue a => String -> a -> LP m ()
addMeta field val = updateState $ \st ->
  st{ stateMeta = addMetaField field val $ stateMeta st }

splitBibs :: String -> [Inlines]
splitBibs = map (str . flip replaceExtension "bib" . trim) . splitBy (==',')

setCaption :: PandocMonad m => LP m Blocks
setCaption = do
  ils <- tok
  mblabel <- option Nothing $
               try $ spaces' >> controlSeq "label" >> (Just <$> tok)
  let ils' = case mblabel of
                  Just lab -> ils <> spanWith
                                ("",[],[("data-label", stringify lab)]) mempty
                  Nothing  -> ils
  updateState $ \st -> st{ stateCaption = Just ils' }
  return mempty

resetCaption :: PandocMonad m => LP m ()
resetCaption = updateState $ \st -> st{ stateCaption = Nothing }

authors :: PandocMonad m => LP m ()
authors = try $ do
  bgroup
  let oneAuthor = mconcat <$>
       many1 (notFollowedBy' (controlSeq "and") >>
               (inline <|> mempty <$ blockCommand))
               -- skip e.g. \vspace{10pt}
  auths <- sepBy oneAuthor (controlSeq "and")
  egroup
  addMeta "author" (map trimInlines auths)

section :: PandocMonad m => Attr -> Int -> LP m Blocks
section (ident, classes, kvs) lvl = do
  skipopts
  contents <- grouped inline
  lab <- option ident $ try (spaces' >> controlSeq "label" >> spaces' >> braced)
  attr' <- registerHeader (lab, classes, kvs) contents
  return $ headerWith attr' lvl contents

inlineCommand :: PandocMonad m => LP m Inlines
inlineCommand = try $ do
  (name, raw') <- withRaw anyControlSeq
  guard $ name /= "begin" && name /= "end"
  star <- option "" (string "*")
  let name' = name ++ star
  let raw = do
        guard $ not (isBlockCommand name)
        rawargs <- withRaw
                (skipangles *> skipopts *> option "" dimenarg *> many braced)
        let rawcommand = raw' ++ star ++ snd rawargs
        transformed <- applyMacros' rawcommand
        exts <- getOption readerExtensions
        if transformed /= rawcommand
           then parseFromString inlines transformed
           else if extensionEnabled Ext_raw_tex exts
                   then return $ rawInline "latex" rawcommand
                   else ignore rawcommand
  (lookupListDefault raw [name',name] inlineCommands <*
      optional (try (string "{}")))

unlessParseRaw :: PandocMonad m => LP m ()
unlessParseRaw = getOption readerExtensions >>=
                 guard . not . extensionEnabled Ext_raw_tex

isBlockCommand :: String -> Bool
isBlockCommand s = s `M.member` (blockCommands :: M.Map String (LP PandocPure Blocks))


inlineEnvironments :: PandocMonad m => M.Map String (LP m Inlines)
inlineEnvironments = M.fromList
  [ ("displaymath", mathEnv id Nothing "displaymath")
  , ("math", math <$> verbEnv "math")
  , ("equation", mathEnv id Nothing "equation")
  , ("equation*", mathEnv id Nothing "equation*")
  , ("gather", mathEnv id (Just "gathered") "gather")
  , ("gather*", mathEnv id (Just "gathered") "gather*")
  , ("multline", mathEnv id (Just "gathered") "multline")
  , ("multline*", mathEnv id (Just "gathered") "multline*")
  , ("eqnarray", mathEnv id (Just "aligned") "eqnarray")
  , ("eqnarray*", mathEnv id (Just "aligned") "eqnarray*")
  , ("align", mathEnv id (Just "aligned") "align")
  , ("align*", mathEnv id (Just "aligned") "align*")
  , ("alignat", mathEnv id (Just "aligned") "alignat")
  , ("alignat*", mathEnv id (Just "aligned") "alignat*")
  ]

inlineCommands :: PandocMonad m => M.Map String (LP m Inlines)
inlineCommands = M.fromList $
  [ ("emph", extractSpaces emph <$> tok)
  , ("textit", extractSpaces emph <$> tok)
  , ("textsl", extractSpaces emph <$> tok)
  , ("textsc", extractSpaces smallcaps <$> tok)
  , ("textsf", extractSpaces (spanWith ("",["sans-serif"],[])) <$> tok)
  , ("textmd", extractSpaces (spanWith ("",["medium"],[])) <$> tok)
  , ("textrm", extractSpaces (spanWith ("",["roman"],[])) <$> tok)
  , ("textup", extractSpaces (spanWith ("",["upright"],[])) <$> tok)
  , ("texttt", (code . stringify . toList) <$> tok)
  , ("sout", extractSpaces strikeout <$> tok)
  , ("textsuperscript", extractSpaces superscript <$> tok)
  , ("textsubscript", extractSpaces subscript <$> tok)
  , ("textbackslash", lit "\\")
  , ("backslash", lit "\\")
  , ("slash", lit "/")
  , ("textbf", extractSpaces strong <$> tok)
  , ("textnormal", extractSpaces (spanWith ("",["nodecor"],[])) <$> tok)
  , ("ldots", lit "…")
  , ("dots", lit "…")
  , ("mdots", lit "…")
  , ("sim", lit "~")
  , ("label", unlessParseRaw >> (inBrackets <$> tok))
  , ("ref", unlessParseRaw >> (inBrackets <$> tok))
  , ("textgreek", tok)
  , ("sep", lit ",")
  , ("cref", unlessParseRaw >> (inBrackets <$> tok))  -- from cleveref.sty
  , ("(", mathInline $ manyTill anyChar (try $ string "\\)"))
  , ("[", mathDisplay $ manyTill anyChar (try $ string "\\]"))
  , ("ensuremath", mathInline braced)
  , ("texorpdfstring", (\_ x -> x) <$> tok <*> tok)
  , ("P", lit "¶")
  , ("S", lit "§")
  , ("$", lit "$")
  , ("%", lit "%")
  , ("&", lit "&")
  , ("#", lit "#")
  , ("_", lit "_")
  , ("{", lit "{")
  , ("}", lit "}")
  -- old TeX commands
  , ("em", extractSpaces emph <$> inlines)
  , ("it", extractSpaces emph <$> inlines)
  , ("sl", extractSpaces emph <$> inlines)
  , ("bf", extractSpaces strong <$> inlines)
  , ("rm", inlines)
  , ("itshape", extractSpaces emph <$> inlines)
  , ("slshape", extractSpaces emph <$> inlines)
  , ("scshape", extractSpaces smallcaps <$> inlines)
  , ("bfseries", extractSpaces strong <$> inlines)
  , ("/", pure mempty) -- italic correction
  , ("aa", lit "å")
  , ("AA", lit "Å")
  , ("ss", lit "ß")
  , ("o", lit "ø")
  , ("O", lit "Ø")
  , ("L", lit "Ł")
  , ("l", lit "ł")
  , ("ae", lit "æ")
  , ("AE", lit "Æ")
  , ("oe", lit "œ")
  , ("OE", lit "Œ")
  , ("pounds", lit "£")
  , ("euro", lit "€")
  , ("copyright", lit "©")
  , ("textasciicircum", lit "^")
  , ("textasciitilde", lit "~")
  , ("H", try $ tok >>= accent hungarumlaut)
  , ("`", option (str "`") $ try $ tok >>= accent grave)
  , ("'", option (str "'") $ try $ tok >>= accent acute)
  , ("^", option (str "^") $ try $ tok >>= accent circ)
  , ("~", option (str "~") $ try $ tok >>= accent tilde)
  , ("\"", option (str "\"") $ try $ tok >>= accent umlaut)
  , (".", option (str ".") $ try $ tok >>= accent dot)
  , ("=", option (str "=") $ try $ tok >>= accent macron)
  , ("c", option (str "c") $ try $ tok >>= accent cedilla)
  , ("v", option (str "v") $ try $ tok >>= accent hacek)
  , ("u", option (str "u") $ try $ tok >>= accent breve)
  , ("i", lit "i")
  , ("\\", linebreak <$ (optional (bracketed inline) *> spaces'))
  , (",", pure mempty)
  , ("@", pure mempty)
  , (" ", lit "\160")
  , ("ps", pure $ str "PS." <> space)
  , ("TeX", lit "TeX")
  , ("LaTeX", lit "LaTeX")
  , ("bar", lit "|")
  , ("textless", lit "<")
  , ("textgreater", lit ">")
  , ("thanks", note <$> grouped block)
  , ("footnote", note <$> grouped block)
  , ("verb", doverb)
  , ("lstinline", dolstinline)
  , ("Verb", doverb)
  , ("url", (unescapeURL <$> braced) >>= \url ->
       pure (link url "" (str url)))
  , ("href", (unescapeURL <$> braced <* optional sp) >>= \url ->
       tok >>= \lab ->
         pure (link url "" lab))
  , ("includegraphics", do options <- option [] keyvals
                           src <- unescapeURL . removeDoubleQuotes <$> braced
                           mkImage options src)
  , ("enquote", enquote)
  , ("cite", citation "cite" NormalCitation False)
  , ("Cite", citation "Cite" NormalCitation False)
  , ("citep", citation "citep" NormalCitation False)
  , ("citep*", citation "citep*" NormalCitation False)
  , ("citeal", citation "citeal" NormalCitation False)
  , ("citealp", citation "citealp" NormalCitation False)
  , ("citealp*", citation "citealp*" NormalCitation False)
  , ("autocite", citation "autocite" NormalCitation False)
  , ("smartcite", citation "smartcite" NormalCitation False)
  , ("footcite", inNote <$> citation "footcite" NormalCitation False)
  , ("parencite", citation "parencite" NormalCitation False)
  , ("supercite", citation "supercite" NormalCitation False)
  , ("footcitetext", inNote <$> citation "footcitetext" NormalCitation False)
  , ("citeyearpar", citation "citeyearpar" SuppressAuthor False)
  , ("citeyear", citation "citeyear" SuppressAuthor False)
  , ("autocite*", citation "autocite*" SuppressAuthor False)
  , ("cite*", citation "cite*" SuppressAuthor False)
  , ("parencite*", citation "parencite*" SuppressAuthor False)
  , ("textcite", citation "textcite" AuthorInText False)
  , ("citet", citation "citet" AuthorInText False)
  , ("citet*", citation "citet*" AuthorInText False)
  , ("citealt", citation "citealt" AuthorInText False)
  , ("citealt*", citation "citealt*" AuthorInText False)
  , ("textcites", citation "textcites" AuthorInText True)
  , ("cites", citation "cites" NormalCitation True)
  , ("autocites", citation "autocites" NormalCitation True)
  , ("footcites", inNote <$> citation "footcites" NormalCitation True)
  , ("parencites", citation "parencites" NormalCitation True)
  , ("supercites", citation "supercites" NormalCitation True)
  , ("footcitetexts", inNote <$> citation "footcitetexts" NormalCitation True)
  , ("Autocite", citation "Autocite" NormalCitation False)
  , ("Smartcite", citation "Smartcite" NormalCitation False)
  , ("Footcite", citation "Footcite" NormalCitation False)
  , ("Parencite", citation "Parencite" NormalCitation False)
  , ("Supercite", citation "Supercite" NormalCitation False)
  , ("Footcitetext", inNote <$> citation "Footcitetext" NormalCitation False)
  , ("Citeyearpar", citation "Citeyearpar" SuppressAuthor False)
  , ("Citeyear", citation "Citeyear" SuppressAuthor False)
  , ("Autocite*", citation "Autocite*" SuppressAuthor False)
  , ("Cite*", citation "Cite*" SuppressAuthor False)
  , ("Parencite*", citation "Parencite*" SuppressAuthor False)
  , ("Textcite", citation "Textcite" AuthorInText False)
  , ("Textcites", citation "Textcites" AuthorInText True)
  , ("Cites", citation "Cites" NormalCitation True)
  , ("Autocites", citation "Autocites" NormalCitation True)
  , ("Footcites", citation "Footcites" NormalCitation True)
  , ("Parencites", citation "Parencites" NormalCitation True)
  , ("Supercites", citation "Supercites" NormalCitation True)
  , ("Footcitetexts", inNote <$> citation "Footcitetexts" NormalCitation True)
  , ("citetext", complexNatbibCitation NormalCitation)
  , ("citeauthor", (try (tok *> optional sp *> controlSeq "citetext") *>
                        complexNatbibCitation AuthorInText)
                   <|> citation "citeauthor" AuthorInText False)
  , ("nocite", mempty <$ (citation "nocite" NormalCitation False >>=
                          addMeta "nocite"))
  , ("hypertarget", braced >> tok)
  -- siuntix
  , ("SI", dosiunitx)
  ] ++ map ignoreInlines
  -- these commands will be ignored unless --parse-raw is specified,
  -- in which case they will appear as raw latex blocks:
  [ "index"
  , "hspace"
  , "vspace"
  , "newpage"
  , "clearpage"
  , "pagebreak"
  ]

mkImage :: PandocMonad m => [(String, String)] -> String -> LP m Inlines
mkImage options src = do
   let replaceTextwidth (k,v) = case numUnit v of
                                  Just (num, "\\textwidth") -> (k, showFl (num * 100) ++ "%")
                                  _ -> (k, v)
   let kvs = map replaceTextwidth $ filter (\(k,_) -> k `elem` ["width", "height"]) options
   let attr = ("",[], kvs)
   let alt = str "image"
   case takeExtension src of
        "" -> do
              defaultExt <- getOption readerDefaultImageExtension
              return $ imageWith attr (addExtension src defaultExt) "" alt
        _  -> return $ imageWith attr src "" alt

inNote :: Inlines -> Inlines
inNote ils =
  note $ para $ ils <> str "."

unescapeURL :: String -> String
unescapeURL ('\\':x:xs) | isEscapable x = x:unescapeURL xs
  where isEscapable c = c `elem` ("#$%&~_^\\{}" :: String)
unescapeURL (x:xs) = x:unescapeURL xs
unescapeURL [] = ""

enquote :: PandocMonad m => LP m Inlines
enquote = do
  skipopts
  context <- stateQuoteContext <$> getState
  if context == InDoubleQuote
     then singleQuoted <$> withQuoteContext InSingleQuote tok
     else doubleQuoted <$> withQuoteContext InDoubleQuote tok

doverb :: PandocMonad m => LP m Inlines
doverb = do
  marker <- anyChar
  code <$> manyTill (satisfy (/='\n')) (char marker)

dolstinline :: PandocMonad m => LP m Inlines
dolstinline = do
  options <- option [] keyvals
  let classes = maybeToList $ lookup "language" options >>= fromListingsLanguage
  marker <- char '{' <|> anyChar 
  codeWith ("",classes,[]) <$> manyTill (satisfy (/='\n')) (char '}' <|> char marker)

doLHSverb :: PandocMonad m => LP m Inlines
doLHSverb = codeWith ("",["haskell"],[]) <$> manyTill (satisfy (/='\n')) (char '|')

-- converts e.g. \SI{1}[\$]{} to "$ 1" or \SI{1}{\euro} to "1 €"
dosiunitx :: PandocMonad m => LP m Inlines
dosiunitx = do
  skipopts
  value <- tok
  valueprefix <- option "" $ char '[' >> (mconcat <$> manyTill tok (char ']'))
  unit <- tok
  let emptyOr160 "" = ""
      emptyOr160 _  = "\160"
  return . mconcat $ [valueprefix, 
                      emptyOr160 valueprefix,
                      value, 
                      emptyOr160 unit,
                      unit]

lit :: String -> LP m Inlines
lit = pure . str

accent :: (Char -> String) -> Inlines -> LP m Inlines
accent f ils =
  case toList ils of
       (Str (x:xs) : ys) -> return $ fromList (Str (f x ++ xs) : ys)
       []                -> mzero
       _                 -> return ils

grave :: Char -> String
grave 'A' = "À"
grave 'E' = "È"
grave 'I' = "Ì"
grave 'O' = "Ò"
grave 'U' = "Ù"
grave 'a' = "à"
grave 'e' = "è"
grave 'i' = "ì"
grave 'o' = "ò"
grave 'u' = "ù"
grave c   = [c]

acute :: Char -> String
acute 'A' = "Á"
acute 'E' = "É"
acute 'I' = "Í"
acute 'O' = "Ó"
acute 'U' = "Ú"
acute 'Y' = "Ý"
acute 'a' = "á"
acute 'e' = "é"
acute 'i' = "í"
acute 'o' = "ó"
acute 'u' = "ú"
acute 'y' = "ý"
acute 'C' = "Ć"
acute 'c' = "ć"
acute 'L' = "Ĺ"
acute 'l' = "ĺ"
acute 'N' = "Ń"
acute 'n' = "ń"
acute 'R' = "Ŕ"
acute 'r' = "ŕ"
acute 'S' = "Ś"
acute 's' = "ś"
acute 'Z' = "Ź"
acute 'z' = "ź"
acute c   = [c]

circ :: Char -> String
circ 'A' = "Â"
circ 'E' = "Ê"
circ 'I' = "Î"
circ 'O' = "Ô"
circ 'U' = "Û"
circ 'a' = "â"
circ 'e' = "ê"
circ 'i' = "î"
circ 'o' = "ô"
circ 'u' = "û"
circ 'C' = "Ĉ"
circ 'c' = "ĉ"
circ 'G' = "Ĝ"
circ 'g' = "ĝ"
circ 'H' = "Ĥ"
circ 'h' = "ĥ"
circ 'J' = "Ĵ"
circ 'j' = "ĵ"
circ 'S' = "Ŝ"
circ 's' = "ŝ"
circ 'W' = "Ŵ"
circ 'w' = "ŵ"
circ 'Y' = "Ŷ"
circ 'y' = "ŷ"
circ c   = [c]

tilde :: Char -> String
tilde 'A' = "Ã"
tilde 'a' = "ã"
tilde 'O' = "Õ"
tilde 'o' = "õ"
tilde 'I' = "Ĩ"
tilde 'i' = "ĩ"
tilde 'U' = "Ũ"
tilde 'u' = "ũ"
tilde 'N' = "Ñ"
tilde 'n' = "ñ"
tilde c   = [c]

umlaut :: Char -> String
umlaut 'A' = "Ä"
umlaut 'E' = "Ë"
umlaut 'I' = "Ï"
umlaut 'O' = "Ö"
umlaut 'U' = "Ü"
umlaut 'a' = "ä"
umlaut 'e' = "ë"
umlaut 'i' = "ï"
umlaut 'o' = "ö"
umlaut 'u' = "ü"
umlaut c   = [c]

hungarumlaut :: Char -> String
hungarumlaut 'A' = "A̋"
hungarumlaut 'E' = "E̋"
hungarumlaut 'I' = "I̋"
hungarumlaut 'O' = "Ő"
hungarumlaut 'U' = "Ű"
hungarumlaut 'Y' = "ӳ"
hungarumlaut 'a' = "a̋"
hungarumlaut 'e' = "e̋"
hungarumlaut 'i' = "i̋"
hungarumlaut 'o' = "ő"
hungarumlaut 'u' = "ű"
hungarumlaut 'y' = "ӳ"
hungarumlaut c   = [c]

dot :: Char -> String
dot 'C' = "Ċ"
dot 'c' = "ċ"
dot 'E' = "Ė"
dot 'e' = "ė"
dot 'G' = "Ġ"
dot 'g' = "ġ"
dot 'I' = "İ"
dot 'Z' = "Ż"
dot 'z' = "ż"
dot c   = [c]

macron :: Char -> String
macron 'A' = "Ā"
macron 'E' = "Ē"
macron 'I' = "Ī"
macron 'O' = "Ō"
macron 'U' = "Ū"
macron 'a' = "ā"
macron 'e' = "ē"
macron 'i' = "ī"
macron 'o' = "ō"
macron 'u' = "ū"
macron c   = [c]

cedilla :: Char -> String
cedilla 'c' = "ç"
cedilla 'C' = "Ç"
cedilla 's' = "ş"
cedilla 'S' = "Ş"
cedilla 't' = "ţ"
cedilla 'T' = "Ţ"
cedilla 'e' = "ȩ"
cedilla 'E' = "Ȩ"
cedilla 'h' = "ḩ"
cedilla 'H' = "Ḩ"
cedilla 'o' = "o̧"
cedilla 'O' = "O̧"
cedilla c   = [c]

hacek :: Char -> String
hacek 'A' = "Ǎ"
hacek 'a' = "ǎ"
hacek 'C' = "Č"
hacek 'c' = "č"
hacek 'D' = "Ď"
hacek 'd' = "ď"
hacek 'E' = "Ě"
hacek 'e' = "ě"
hacek 'G' = "Ǧ"
hacek 'g' = "ǧ"
hacek 'H' = "Ȟ"
hacek 'h' = "ȟ"
hacek 'I' = "Ǐ"
hacek 'i' = "ǐ"
hacek 'j' = "ǰ"
hacek 'K' = "Ǩ"
hacek 'k' = "ǩ"
hacek 'L' = "Ľ"
hacek 'l' = "ľ"
hacek 'N' = "Ň"
hacek 'n' = "ň"
hacek 'O' = "Ǒ"
hacek 'o' = "ǒ"
hacek 'R' = "Ř"
hacek 'r' = "ř"
hacek 'S' = "Š"
hacek 's' = "š"
hacek 'T' = "Ť"
hacek 't' = "ť"
hacek 'U' = "Ǔ"
hacek 'u' = "ǔ"
hacek 'Z' = "Ž"
hacek 'z' = "ž"
hacek c   = [c]

breve :: Char -> String
breve 'A' = "Ă"
breve 'a' = "ă"
breve 'E' = "Ĕ"
breve 'e' = "ĕ"
breve 'G' = "Ğ"
breve 'g' = "ğ"
breve 'I' = "Ĭ"
breve 'i' = "ĭ"
breve 'O' = "Ŏ"
breve 'o' = "ŏ"
breve 'U' = "Ŭ"
breve 'u' = "ŭ"
breve c   = [c]

tok :: PandocMonad m => LP m Inlines
tok = try $ grouped inline <|> inlineCommand <|> str <$> count 1 inlineChar

opt :: PandocMonad m => LP m Inlines
opt = bracketed inline

rawopt :: PandocMonad m => LP m String
rawopt = do
  contents <- bracketed (many1 (noneOf "[]") <|> try (string "\\]") <|>
                   try (string "\\[") <|> rawopt)
  optional sp
  return $ "[" ++ contents ++ "]"

skipopts :: PandocMonad m => LP m ()
skipopts = skipMany rawopt

-- opts in angle brackets are used in beamer
rawangle :: PandocMonad m => LP m ()
rawangle = try $ do
  char '<'
  skipMany (noneOf ">")
  char '>'
  return ()

skipangles :: PandocMonad m => LP m ()
skipangles = skipMany rawangle

inlineText :: PandocMonad m => LP m Inlines
inlineText = str <$> many1 inlineChar

inlineChar :: PandocMonad m => LP m Char
inlineChar = noneOf "\\$%&~#{}^'`\"‘’“”-[] \t\n"

environment :: PandocMonad m => LP m Blocks
environment = do
  controlSeq "begin"
  name <- braced
  M.findWithDefault mzero name environments
    <|> rawEnv name

inlineEnvironment :: PandocMonad m => LP m Inlines
inlineEnvironment = try $ do
  controlSeq "begin"
  name <- braced
  M.findWithDefault mzero name inlineEnvironments

rawEnv :: PandocMonad m => String -> LP m Blocks
rawEnv name = do
  exts <- getOption readerExtensions
  let parseRaw = extensionEnabled Ext_raw_tex exts
  rawOptions <- mconcat <$> many rawopt
  let beginCommand = "\\begin{" ++ name ++ "}" ++ rawOptions
  pos1 <- getPosition
  (bs, raw) <- withRaw $ env name blocks
  raw' <- applyMacros' $ beginCommand ++ raw
  if raw' /= beginCommand ++ raw
     then parseFromString blocks raw'
     else if parseRaw
          then return $ rawBlock "latex" $ beginCommand ++ raw'
          else do
            unless parseRaw $ do
              report $ SkippedContent beginCommand pos1
            pos2 <- getPosition
            report $ SkippedContent ("\\end{" ++ name ++ "}") pos2
            return bs

----

maybeAddExtension :: String -> FilePath -> FilePath
maybeAddExtension ext fp =
  if null (takeExtension fp)
     then addExtension fp ext
     else fp

include :: PandocMonad m => LP m Blocks
include = do
  fs' <- try $ do
              char '\\'
              name <- try (string "include")
                  <|> try (string "input")
                  <|> try (string "subfile")
                  <|> string "usepackage"
              -- skip options
              skipMany $ try $ char '[' *> manyTill anyChar (char ']')
              fs <- (map trim . splitBy (==',')) <$> braced
              return $ if name == "usepackage"
                          then map (maybeAddExtension ".sty") fs
                          else map (maybeAddExtension ".tex") fs
  dirs <- (splitBy (==':') . fromMaybe ".") <$> lookupEnv "TEXINPUTS"
  mconcat <$> mapM (insertIncludedFile blocks dirs) fs'

inputListing :: PandocMonad m => LP m Blocks
inputListing = do
  pos <- getPosition
  options <- option [] keyvals
  f <- filter (/='"') <$> braced
  dirs <- (splitBy (==':') . fromMaybe ".") <$> lookupEnv "TEXINPUTS"
  mbCode <- readFileFromDirs dirs f
  codeLines <- case mbCode of
                      Just s -> return $ lines s
                      Nothing -> do
                        report $ CouldNotLoadIncludeFile f pos
                        return []
  let (ident,classes,kvs) = parseListingsOptions options
  let language = case lookup "language" options >>= fromListingsLanguage of
                      Just l -> [l]
                      Nothing -> take 1 $ languagesByExtension (takeExtension f)
  let firstline = fromMaybe 1 $ lookup "firstline" options >>= safeRead
  let lastline = fromMaybe (length codeLines) $
                       lookup "lastline" options >>= safeRead
  let codeContents = intercalate "\n" $ take (1 + lastline - firstline) $
                       drop (firstline - 1) codeLines
  return $ codeBlockWith (ident,ordNub (classes ++ language),kvs) codeContents

parseListingsOptions :: [(String, String)] -> Attr
parseListingsOptions options =
  let kvs = [ (if k == "firstnumber"
                  then "startFrom"
                  else k, v) | (k,v) <- options ]
      classes = [ "numberLines" |
                  lookup "numbers" options == Just "left" ]
             ++ maybeToList (lookup "language" options
                     >>= fromListingsLanguage)
  in  (fromMaybe "" (lookup "label" options), classes, kvs)

----

keyval :: PandocMonad m => LP m (String, String)
keyval = try $ do
  key <- many1 alphaNum
  val <- option "" $ char '=' >> many1 (alphaNum <|> char '.' <|> char '\\')
  skipMany spaceChar
  optional (char ',')
  skipMany spaceChar
  return (key, val)


keyvals :: PandocMonad m => LP m [(String, String)]
keyvals = try $ char '[' *> manyTill keyval (char ']')

alltt :: PandocMonad m => String -> LP m Blocks
alltt t = walk strToCode <$> parseFromString blocks
  (substitute " " "\\ " $ substitute "%" "\\%" $
   intercalate "\\\\\n" $ lines t)
  where strToCode (Str s) = Code nullAttr s
        strToCode x       = x

rawLaTeXBlock :: PandocMonad m => LP m String
rawLaTeXBlock = snd <$> try (withRaw (environment <|> blockCommand))

rawLaTeXInline :: PandocMonad m => LP m Inline
rawLaTeXInline = do
  raw <- (snd <$> withRaw inlineCommand)
     <|> (snd <$> withRaw inlineEnvironment)
     <|> (snd <$> withRaw blockCommand)
  RawInline "latex" <$> applyMacros' raw

addImageCaption :: PandocMonad m => Blocks -> LP m Blocks
addImageCaption = walkM go
  where go (Image attr alt (src,tit))
            | not ("fig:" `isPrefixOf` tit) = do
          mbcapt <- stateCaption <$> getState
          return $ case mbcapt of
               Just ils -> Image attr (toList ils) (src, "fig:" ++ tit)
               Nothing  -> Image attr alt (src,tit)
        go x = return x

addTableCaption :: PandocMonad m => Blocks -> LP m Blocks
addTableCaption = walkM go
  where go (Table c als ws hs rs) = do
          mbcapt <- stateCaption <$> getState
          return $ case mbcapt of
               Just ils -> Table (toList ils) als ws hs rs
               Nothing  -> Table c als ws hs rs
        go x = return x

environments :: PandocMonad m => M.Map String (LP m Blocks)
environments = M.fromList
  [ ("document", env "document" blocks <* skipMany anyChar)
  , ("abstract", mempty <$ (env "abstract" blocks >>= addMeta "abstract"))
  , ("letter", env "letter" letterContents)
  , ("minipage", env "minipage" $
         skipopts *> spaces' *> optional braced *> spaces' *> blocks)
  , ("figure", env "figure" $ skipopts *> figure)
  , ("subfigure", env "subfigure" $ skipopts *> tok *> figure)
  , ("center", env "center" blocks)
  , ("longtable",  env "longtable" $
         resetCaption *> simpTable False >>= addTableCaption)
  , ("table",  env "table" $
         resetCaption *> skipopts *> blocks >>= addTableCaption)
  , ("tabular*", env "tabular" $ simpTable True)
  , ("tabular", env "tabular"  $ simpTable False)
  , ("quote", blockQuote <$> env "quote" blocks)
  , ("quotation", blockQuote <$> env "quotation" blocks)
  , ("verse", blockQuote <$> env "verse" blocks)
  , ("itemize", bulletList <$> listenv "itemize" (many item))
  , ("description", definitionList <$> listenv "description" (many descItem))
  , ("enumerate", orderedList')
  , ("alltt", alltt =<< verbEnv "alltt")
  , ("code", guardEnabled Ext_literate_haskell *>
      (codeBlockWith ("",["sourceCode","literate","haskell"],[]) <$>
        verbEnv "code"))
  , ("comment", mempty <$ verbEnv "comment")
  , ("verbatim", codeBlock <$> verbEnv "verbatim")
  , ("Verbatim", fancyverbEnv "Verbatim")
  , ("BVerbatim", fancyverbEnv "BVerbatim")
  , ("lstlisting", do attr <- parseListingsOptions <$> option [] keyvals
                      codeBlockWith attr <$> verbEnv "lstlisting")
  , ("minted",     do options <- option [] keyvals
                      lang <- grouped (many1 $ satisfy (/='}'))
                      let kvs = [ (if k == "firstnumber"
                                      then "startFrom"
                                      else k, v) | (k,v) <- options ]
                      let classes = [ lang | not (null lang) ] ++
                                    [ "numberLines" |
                                      lookup "linenos" options == Just "true" ]
                      let attr = ("",classes,kvs)
                      codeBlockWith attr <$> verbEnv "minted")
  , ("obeylines", parseFromString
                  (para . trimInlines . mconcat <$> many inline) =<<
                  intercalate "\\\\\n" . lines <$> verbEnv "obeylines")
  , ("displaymath", mathEnv para Nothing "displaymath")
  , ("equation", mathEnv para Nothing "equation")
  , ("equation*", mathEnv para Nothing "equation*")
  , ("gather", mathEnv para (Just "gathered") "gather")
  , ("gather*", mathEnv para (Just "gathered") "gather*")
  , ("multline", mathEnv para (Just "gathered") "multline")
  , ("multline*", mathEnv para (Just "gathered") "multline*")
  , ("eqnarray", mathEnv para (Just "aligned") "eqnarray")
  , ("eqnarray*", mathEnv para (Just "aligned") "eqnarray*")
  , ("align", mathEnv para (Just "aligned") "align")
  , ("align*", mathEnv para (Just "aligned") "align*")
  , ("alignat", mathEnv para (Just "aligned") "alignat")
  , ("alignat*", mathEnv para (Just "aligned") "alignat*")
  ]

figure :: PandocMonad m => LP m Blocks
figure = try $ do
  resetCaption
  blocks >>= addImageCaption

letterContents :: PandocMonad m => LP m Blocks
letterContents = do
  bs <- blocks
  st <- getState
  -- add signature (author) and address (title)
  let addr = case lookupMeta "address" (stateMeta st) of
                  Just (MetaBlocks [Plain xs]) ->
                     para $ trimInlines $ fromList xs
                  _ -> mempty
  return $ addr <> bs -- sig added by \closing

closing :: PandocMonad m => LP m Blocks
closing = do
  contents <- tok
  st <- getState
  let extractInlines (MetaBlocks [Plain ys]) = ys
      extractInlines (MetaBlocks [Para ys ]) = ys
      extractInlines _                       = []
  let sigs = case lookupMeta "author" (stateMeta st) of
                  Just (MetaList xs) ->
                    para $ trimInlines $ fromList $
                      intercalate [LineBreak] $ map extractInlines xs
                  _ -> mempty
  return $ para (trimInlines contents) <> sigs

item :: PandocMonad m => LP m Blocks
item = blocks *> controlSeq "item" *> skipopts *> blocks

looseItem :: PandocMonad m => LP m Blocks
looseItem = do
  ctx <- stateParserContext `fmap` getState
  if ctx == ListItemState
     then mzero
     else return mempty

descItem :: PandocMonad m => LP m (Inlines, [Blocks])
descItem = do
  blocks -- skip blocks before item
  controlSeq "item"
  optional sp
  ils <- opt
  bs <- blocks
  return (ils, [bs])

env :: PandocMonad m => String -> LP m a -> LP m a
env name p = p <*
  (try (controlSeq "end" *> braced >>= guard . (== name))
    <?> ("\\end{" ++ name ++ "}"))

listenv :: PandocMonad m => String -> LP m a -> LP m a
listenv name p = try $ do
  oldCtx <- stateParserContext `fmap` getState
  updateState $ \st -> st{ stateParserContext = ListItemState }
  res <- env name p
  updateState $ \st -> st{ stateParserContext = oldCtx }
  return res

mathEnv :: PandocMonad m => (Inlines -> a) -> Maybe String -> String -> LP m a
mathEnv f innerEnv name = f <$> mathDisplay (inner <$> verbEnv name)
   where inner x = case innerEnv of
                      Nothing -> x
                      Just y  -> "\\begin{" ++ y ++ "}\n" ++ x ++
                                    "\\end{" ++ y ++ "}"

verbEnv :: PandocMonad m => String -> LP m String
verbEnv name = do
  skipopts
  optional blankline
  let endEnv = try $ controlSeq "end" *> braced >>= guard . (== name)
  res <- manyTill anyChar endEnv
  return $ stripTrailingNewlines res

fancyverbEnv :: PandocMonad m => String -> LP m Blocks
fancyverbEnv name = do
  options <- option [] keyvals
  let kvs = [ (if k == "firstnumber"
                  then "startFrom"
                  else k, v) | (k,v) <- options ]
  let classes = [ "numberLines" |
                  lookup "numbers" options == Just "left" ]
  let attr = ("",classes,kvs)
  codeBlockWith attr <$> verbEnv name

orderedList' :: PandocMonad m => LP m Blocks
orderedList' = do
  optional sp
  (_, style, delim) <- option (1, DefaultStyle, DefaultDelim) $
                              try $ char '[' *> anyOrderedListMarker <* char ']'
  spaces
  optional $ try $ controlSeq "setlength" *> grouped (controlSeq "itemindent") *> braced
  spaces
  start <- option 1 $ try $ do controlSeq "setcounter"
                               grouped (string "enum" *> many1 (oneOf "iv"))
                               optional sp
                               num <- grouped (many1 digit)
                               spaces
                               return (read num + 1 :: Int)
  bs <- listenv "enumerate" (many item)
  return $ orderedListWith (start, style, delim) bs

paragraph :: PandocMonad m => LP m Blocks
paragraph = do
  x <- trimInlines . mconcat <$> many1 inline
  if x == mempty
     then return mempty
     else return $ para x

preamble :: PandocMonad m => LP m Blocks
preamble = mempty <$> manyTill preambleBlock beginDoc
  where beginDoc = lookAhead $ try $ controlSeq "begin" *> string "{document}"
        preambleBlock =  void comment
                     <|> void sp
                     <|> void blanklines
                     <|> void include
                     <|> void macro
                     <|> void blockCommand
                     <|> void anyControlSeq
                     <|> void braced
                     <|> void anyChar

-------

-- citations

addPrefix :: [Inline] -> [Citation] -> [Citation]
addPrefix p (k:ks) = k {citationPrefix = p ++ citationPrefix k} : ks
addPrefix _ _      = []

addSuffix :: [Inline] -> [Citation] -> [Citation]
addSuffix s ks@(_:_) =
  let k = last ks
  in  init ks ++ [k {citationSuffix = citationSuffix k ++ s}]
addSuffix _ _ = []

simpleCiteArgs :: PandocMonad m => LP m [Citation]
simpleCiteArgs = try $ do
  first  <- optionMaybe $ toList <$> opt
  second <- optionMaybe $ toList <$> opt
  keys <- try $ bgroup *> (manyTill citationLabel egroup)
  let (pre, suf) = case (first  , second ) of
        (Just s , Nothing) -> (mempty, s )
        (Just s , Just t ) -> (s , t )
        _                  -> (mempty, mempty)
      conv k = Citation { citationId      = k
                        , citationPrefix  = []
                        , citationSuffix  = []
                        , citationMode    = NormalCitation
                        , citationHash    = 0
                        , citationNoteNum = 0
                        }
  return $ addPrefix pre $ addSuffix suf $ map conv keys

citationLabel :: PandocMonad m => LP m String
citationLabel  = optional sp *>
  (many1 (satisfy isBibtexKeyChar)
          <* optional sp
          <* optional (char ',')
          <* optional sp)
  where isBibtexKeyChar c = isAlphaNum c || c `elem` (".:;?!`'()/*@_+=-[]" :: String)

cites :: PandocMonad m => CitationMode -> Bool -> LP m [Citation]
cites mode multi = try $ do
  cits <- if multi
             then many1 simpleCiteArgs
             else count 1 simpleCiteArgs
  let cs = concat cits
  return $ case mode of
        AuthorInText -> case cs of
                             (c:rest) -> c {citationMode = mode} : rest
                             []       -> []
        _            -> map (\a -> a {citationMode = mode}) cs

citation :: PandocMonad m => String -> CitationMode -> Bool -> LP m Inlines
citation name mode multi = do
  (c,raw) <- withRaw $ cites mode multi
  return $ cite c (rawInline "latex" $ "\\" ++ name ++ raw)

complexNatbibCitation :: PandocMonad m => CitationMode -> LP m Inlines
complexNatbibCitation mode = try $ do
  let ils = (toList . trimInlines . mconcat) <$>
              many (notFollowedBy (oneOf "\\};") >> inline)
  let parseOne = try $ do
                   skipSpaces
                   pref  <- ils
                   cit' <- inline -- expect a citation
                   let citlist = toList cit'
                   cits' <- case citlist of
                                 [Cite cs _] -> return cs
                                 _           -> mzero
                   suff  <- ils
                   skipSpaces
                   optional $ char ';'
                   return $ addPrefix pref $ addSuffix suff cits'
  (c:cits, raw) <- withRaw $ grouped parseOne
  return $ cite (c{ citationMode = mode }:cits)
           (rawInline "latex" $ "\\citetext" ++ raw)

-- tables

parseAligns :: PandocMonad m => LP m [(String, Alignment, String)]
parseAligns = try $ do
  bgroup
  let maybeBar = skipMany $ sp <|> () <$ char '|' <|> () <$ (char '@' >> braced)
  maybeBar
  let cAlign = AlignCenter <$ char 'c'
  let lAlign = AlignLeft <$ char 'l'
  let rAlign = AlignRight <$ char 'r'
  let parAlign = AlignLeft <$ (char 'p' >> braced)
  let alignChar = cAlign <|> lAlign <|> rAlign <|> parAlign
  let alignPrefix = char '>' >> braced
  let alignSuffix = char '<' >> braced
  let alignSpec = do
        spaces
        pref <- option "" alignPrefix
        spaces
        ch <- alignChar
        spaces
        suff <- option "" alignSuffix
        return (pref, ch, suff)
  aligns' <- sepEndBy alignSpec maybeBar
  spaces
  egroup
  spaces
  return $ aligns'

hline :: PandocMonad m => LP m ()
hline = try $ do
  spaces'
  controlSeq "hline" <|>
    -- booktabs rules:
    controlSeq "toprule" <|>
    controlSeq "bottomrule" <|>
    controlSeq "midrule" <|>
    controlSeq "endhead" <|>
    controlSeq "endfirsthead"
  spaces'
  optional $ bracketed (many1 (satisfy (/=']')))
  return ()

lbreak :: PandocMonad m => LP m ()
lbreak = () <$ try (spaces' *>
                    (controlSeq "\\" <|> controlSeq "tabularnewline") <*
                    spaces')

amp :: PandocMonad m => LP m ()
amp = () <$ try (spaces' *> char '&' <* spaces')

parseTableRow :: PandocMonad m
              => Int  -- ^ number of columns
              -> [String] -- ^ prefixes
              -> [String] -- ^ suffixes
              -> LP m [Blocks]
parseTableRow cols prefixes suffixes = try $ do
  let tableCellRaw = many (notFollowedBy
                       (amp <|> lbreak <|>
                         (() <$ try (string "\\end"))) >> anyChar)
  let minipage = try $ controlSeq "begin" *> string "{minipage}" *>
          env "minipage"
          (skipopts *> spaces' *> optional braced *> spaces' *> blocks)
  let tableCell = minipage <|>
            ((plain . trimInlines . mconcat) <$> many inline)
  rawcells <- sepBy1 tableCellRaw amp
  guard $ length rawcells == cols
  let rawcells' = zipWith3 (\c p s -> p ++ trim c ++ s)
                      rawcells prefixes suffixes
  cells' <- mapM (parseFromString tableCell) rawcells'
  let numcells = length cells'
  guard $ numcells <= cols && numcells >= 1
  guard $ cells' /= [mempty]
  -- note:  a & b in a three-column table leaves an empty 3rd cell:
  let cells'' = cells' ++ replicate (cols - numcells) mempty
  spaces'
  return cells''

spaces' :: PandocMonad m => LP m ()
spaces' = spaces *> skipMany (comment *> spaces)

simpTable :: PandocMonad m => Bool -> LP m Blocks
simpTable hasWidthParameter = try $ do
  when hasWidthParameter $ () <$ (spaces' >> tok)
  skipopts
  (prefixes, aligns, suffixes) <- unzip3 <$> parseAligns
  let cols = length aligns
  optional $ controlSeq "caption" *> skipopts *> setCaption
  optional lbreak
  spaces'
  skipMany hline
  spaces'
  header' <- option [] $ try (parseTableRow cols prefixes suffixes <*
                                   lbreak <* many1 hline)
  spaces'
  rows <- sepEndBy (parseTableRow cols prefixes suffixes)
                    (lbreak <* optional (skipMany hline))
  spaces'
  optional $ controlSeq "caption" *> skipopts *> setCaption
  optional lbreak
  spaces'
  let header'' = if null header'
                    then replicate cols mempty
                    else header'
  lookAhead $ controlSeq "end" -- make sure we're at end
  return $ table mempty (zip aligns (repeat 0)) header'' rows

removeDoubleQuotes :: String -> String
removeDoubleQuotes ('"':xs) =
  case reverse xs of
       '"':ys -> reverse ys
       _      -> '"':xs
removeDoubleQuotes xs = xs