aboutsummaryrefslogtreecommitdiff
path: root/src/Text/Pandoc/Readers/Muse.hs
blob: 26da5788343c80437d557e91e74bb755fcad97ac (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
{-# LANGUAGE FlexibleContexts      #-}
{-
  Copyright (C) 2017-2018 Alexander Krotov <ilabdsf@gmail.com>

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.Muse
   Copyright   : Copyright (C) 2017-2018 Alexander Krotov
   License     : GNU GPL, version 2 or above

   Maintainer  : Alexander Krotov <ilabdsf@gmail.com>
   Stability   : alpha
   Portability : portable

Conversion of Muse text to 'Pandoc' document.
-}
{-
TODO:
- Page breaks (five "*")
- Org tables
- table.el tables
- Images with attributes (floating and width)
- Citations and <biblio>
- <play> environment
-}
module Text.Pandoc.Readers.Muse (readMuse) where

import Control.Monad
import Control.Monad.Except (throwError)
import Data.Char (isLetter)
import Data.Default
import Data.List (stripPrefix, intercalate)
import Data.List.Split (splitOn)
import qualified Data.Map as M
import qualified Data.Set as Set
import Data.Maybe (fromMaybe, isNothing)
import Data.Text (Text, unpack)
import System.FilePath (takeExtension)
import Text.HTML.TagSoup
import Text.Pandoc.Builder (Blocks, Inlines)
import qualified Text.Pandoc.Builder as B
import Text.Pandoc.Class (PandocMonad (..))
import Text.Pandoc.Definition
import Text.Pandoc.Logging
import Text.Pandoc.Options
import Text.Pandoc.Parsing hiding (F)
import Text.Pandoc.Readers.HTML (htmlTag)
import Text.Pandoc.Shared (crFilter, underlineSpan)

-- | Read Muse from an input string and return a Pandoc document.
readMuse :: PandocMonad m
         => ReaderOptions
         -> Text
         -> m Pandoc
readMuse opts s = do
  res <- readWithM parseMuse def{ museOptions = opts } (unpack (crFilter s))
  case res of
       Left e  -> throwError e
       Right d -> return d

type F = Future MuseState

data MuseState = MuseState { museMeta :: F Meta -- ^ Document metadata
                           , museOptions :: ReaderOptions
                           , museHeaders :: M.Map Inlines String -- ^ List of headers and ids (used for implicit ref links)
                           , museIdentifierList :: Set.Set String
                           , museLastStrPos :: Maybe SourcePos -- ^ Position after last str parsed
                           , museLogMessages :: [LogMessage]
                           , museNotes :: M.Map String (SourcePos, F Blocks)
                           , museInLink :: Bool
                           , museInPara :: Bool
                           }

instance Default MuseState where
  def = defaultMuseState

defaultMuseState :: MuseState
defaultMuseState = MuseState { museMeta = return nullMeta
                             , museOptions = def
                             , museHeaders = M.empty
                             , museIdentifierList = Set.empty
                             , museLastStrPos = Nothing
                             , museLogMessages = []
                             , museNotes = M.empty
                             , museInLink = False
                             , museInPara = False
                             }

type MuseParser = ParserT String MuseState

instance HasReaderOptions MuseState where
  extractReaderOptions = museOptions

instance HasHeaderMap MuseState where
  extractHeaderMap     = museHeaders
  updateHeaderMap f st = st{ museHeaders = f $ museHeaders st }

instance HasIdentifierList MuseState where
  extractIdentifierList     = museIdentifierList
  updateIdentifierList f st = st{ museIdentifierList = f $ museIdentifierList st }

instance HasLastStrPosition MuseState where
  setLastStrPos pos st = st{ museLastStrPos = Just pos }
  getLastStrPos st     = museLastStrPos st

instance HasLogMessages MuseState where
  addLogMessage m s = s{ museLogMessages = m : museLogMessages s }
  getLogMessages = reverse . museLogMessages

--
-- main parser
--

parseMuse :: PandocMonad m => MuseParser m Pandoc
parseMuse = do
  many directive
  blocks <- parseBlocks
  st <- getState
  let doc = runF (do Pandoc _ bs <- B.doc <$> blocks
                     meta <- museMeta st
                     return $ Pandoc meta bs) st
  reportLogMessages
  return doc

--
-- utility functions
--

eol :: Stream s m Char => ParserT s st m ()
eol = void newline <|> eof

htmlElement :: PandocMonad m => String -> MuseParser m (Attr, String)
htmlElement tag = try $ do
  (TagOpen _ attr, _) <- htmlTag (~== TagOpen tag [])
  content <- manyTill anyChar endtag
  return (htmlAttrToPandoc attr, content)
  where
    endtag = void $ htmlTag (~== TagClose tag)

htmlBlock :: PandocMonad m => String -> MuseParser m (Attr, String)
htmlBlock tag = try $ do
  res <- htmlElement tag
  manyTill spaceChar eol
  return res

htmlAttrToPandoc :: [Attribute String] -> Attr
htmlAttrToPandoc attrs = (ident, classes, keyvals)
  where
    ident   = fromMaybe "" $ lookup "id" attrs
    classes = maybe [] words $ lookup "class" attrs
    keyvals = [(k,v) | (k,v) <- attrs, k /= "id" && k /= "class"]

parseHtmlContent :: PandocMonad m
                 => String -> MuseParser m (Attr, F Blocks)
parseHtmlContent tag = do
  (TagOpen _ attr, _) <- htmlTag (~== TagOpen tag [])
  manyTill spaceChar eol
  content <- parseBlocksTill (manyTill spaceChar endtag)
  manyTill spaceChar eol -- closing tag must be followed by optional whitespace and newline
  return (htmlAttrToPandoc attr, content)
  where
    endtag = void $ htmlTag (~== TagClose tag)

commonPrefix :: String -> String -> String
commonPrefix _ [] = []
commonPrefix [] _ = []
commonPrefix (x:xs) (y:ys)
  | x == y    = x : commonPrefix xs ys
  | otherwise = []

atStart :: PandocMonad m => MuseParser m a -> MuseParser m a
atStart p = do
  pos <- getPosition
  st <- getState
  guard $ museLastStrPos st /= Just pos
  p

someUntil :: (Stream s m t)
          => ParserT s u m a
          -> ParserT s u m b
          -> ParserT s u m ([a], b)
someUntil p end = do
  first <- p
  (rest, e) <- manyUntil p end
  return (first:rest, e)

--
-- directive parsers
--

-- While not documented, Emacs Muse allows "-" in directive name
parseDirectiveKey :: PandocMonad m => MuseParser m String
parseDirectiveKey = do
  char '#'
  many (letter <|> char '-')

parseEmacsDirective :: PandocMonad m => MuseParser m (String, F Inlines)
parseEmacsDirective = do
  key <- parseDirectiveKey
  spaceChar
  value <- trimInlinesF . mconcat <$> manyTill (choice inlineList) eol
  return (key, value)

parseAmuseDirective :: PandocMonad m => MuseParser m (String, F Inlines)
parseAmuseDirective = do
  key <- parseDirectiveKey
  many1 spaceChar
  value <- trimInlinesF . mconcat <$> many1Till inline endOfDirective
  many blankline
  return (key, value)
  where
    endOfDirective = lookAhead $ eof <|> try (newline >> (void blankline <|> void parseDirectiveKey))

directive :: PandocMonad m => MuseParser m ()
directive = do
  ext <- getOption readerExtensions
  (key, value) <- if extensionEnabled Ext_amuse ext then parseAmuseDirective else parseEmacsDirective
  updateState $ \st -> st { museMeta = B.setMeta (translateKey key) <$> value <*> museMeta st }
  where translateKey "cover" = "cover-image"
        translateKey x = x

--
-- block parsers
--

parseBlocks :: PandocMonad m
            => MuseParser m (F Blocks)
parseBlocks =
  try parseEnd <|>
  try blockStart <|>
  try listStart <|>
  try paraStart
  where
    parseEnd = mempty <$ eof
    blockStart = do first <- header <|> blockElements <|> emacsNoteBlock
                    rest <- parseBlocks
                    return $ first B.<> rest
    listStart = do
      updateState (\st -> st { museInPara = False })
      (first, rest) <- anyListUntil parseBlocks <|> amuseNoteBlockUntil parseBlocks
      return $ first B.<> rest
    paraStart = do
      indent <- length <$> many spaceChar
      (first, rest) <- paraUntil parseBlocks
      let first' = if indent >= 2 && indent < 6 then B.blockQuote <$> first else first
      return $ first' B.<> rest

parseBlocksTill :: PandocMonad m
                => MuseParser m a
                -> MuseParser m (F Blocks)
parseBlocksTill end =
  try parseEnd <|>
  try blockStart <|>
  try listStart <|>
  try paraStart
  where
    parseEnd = mempty <$ end
    blockStart = do first <- blockElements
                    rest <- continuation
                    return $ first B.<> rest
    listStart = do
      updateState (\st -> st { museInPara = False })
      (first, e) <- anyListUntil ((Left <$> end) <|> (Right <$> continuation))
      case e of
        Left _ -> return first
        Right rest -> return $ first B.<> rest
    paraStart = do (first, e) <- paraUntil ((Left <$> end) <|> (Right <$> continuation))
                   case e of
                     Left _ -> return first
                     Right rest -> return $ first B.<> rest
    continuation = parseBlocksTill end

listItemContentsUntil :: PandocMonad m
                      => Int
                      -> MuseParser m a
                      -> MuseParser m a
                      -> MuseParser m (F Blocks, a)
listItemContentsUntil col pre end =
  try blockStart <|>
  try listStart <|>
  try paraStart
  where
    parsePre = do e <- pre
                  return (mempty, e)
    parseEnd = do e <- end
                  return (mempty, e)
    paraStart = do
      (first, e) <- paraUntil ((Left <$> pre) <|> (Right <$> continuation) <|> (Left <$> end))
      case e of
        Left ee -> return (first, ee)
        Right (rest, ee) -> return (first B.<> rest, ee)
    blockStart = do first <- blockElements
                    (rest, e) <- parsePre <|> continuation <|> parseEnd
                    return (first B.<> rest, e)
    listStart = do
      updateState (\st -> st { museInPara = False })
      (first, e) <- anyListUntil ((Left <$> pre) <|> (Right <$> continuation) <|> (Left <$> end))
      case e of
        Left ee -> return (first, ee)
        Right (rest, ee) -> return (first B.<> rest, ee)
    continuation = try $ do blank <- optionMaybe blankline
                            skipMany blankline
                            indentWith col
                            updateState (\st -> st { museInPara = museInPara st && isNothing blank })
                            listItemContentsUntil col pre end

parseBlock :: PandocMonad m => MuseParser m (F Blocks)
parseBlock = do
  res <- blockElements <|> para
  trace (take 60 $ show $ B.toList $ runF res def)
  return res
  where para = fst <$> paraUntil (try (eof <|> void (lookAhead blockElements)))

blockElements :: PandocMonad m => MuseParser m (F Blocks)
blockElements = do
  updateState (\st -> st { museInPara = False })
  choice [ mempty <$ blankline
         , comment
         , separator
         , example
         , exampleTag
         , literalTag
         , centerTag
         , rightTag
         , quoteTag
         , divTag
         , verseTag
         , lineBlock
         , table
         , commentTag
         ]

comment :: PandocMonad m => MuseParser m (F Blocks)
comment = try $ do
  char ';'
  optional (spaceChar >> many (noneOf "\n"))
  eol
  return mempty

separator :: PandocMonad m => MuseParser m (F Blocks)
separator = try $ do
  string "----"
  many $ char '-'
  many spaceChar
  eol
  return $ return B.horizontalRule

header :: PandocMonad m => MuseParser m (F Blocks)
header = try $ do
  getPosition >>= \pos -> guard (sourceColumn pos == 1)
  level <- fmap length $ many1 $ char '*'
  guard $ level <= 5
  spaceChar
  content <- trimInlinesF . mconcat <$> manyTill inline eol
  anchorId <- option "" parseAnchor
  attr <- registerHeader (anchorId, [], []) (runF content def)
  return $ B.headerWith attr level <$> content

example :: PandocMonad m => MuseParser m (F Blocks)
example = try $ do
  string "{{{"
  optional blankline
  contents <- manyTill anyChar $ try (optional blankline >> string "}}}")
  return $ return $ B.codeBlock contents

-- Trim up to one newline from the beginning and the end,
-- in case opening and/or closing tags are on separate lines.
chop :: String -> String
chop = lchop . rchop

lchop :: String -> String
lchop s = case s of
                    '\n':ss -> ss
                    _       -> s

rchop :: String -> String
rchop = reverse . lchop . reverse

dropSpacePrefix :: [String] -> [String]
dropSpacePrefix lns =
  map (drop maxIndent) lns
  where flns = filter (not . all (== ' ')) lns
        maxIndent = if null flns then maximum (map length lns) else length $ takeWhile (== ' ') $ foldl1 commonPrefix flns

exampleTag :: PandocMonad m => MuseParser m (F Blocks)
exampleTag = try $ do
  many spaceChar
  (attr, contents) <- htmlBlock "example"
  return $ return $ B.codeBlockWith attr $ rchop $ intercalate "\n" $ dropSpacePrefix $ splitOn "\n" $ lchop contents

literalTag :: PandocMonad m => MuseParser m (F Blocks)
literalTag = do
  guardDisabled Ext_amuse -- Text::Amuse does not support <literal>
  (return . rawBlock) <$> htmlBlock "literal"
  where
    -- FIXME: Emacs Muse inserts <literal> without style into all output formats, but we assume HTML
    format (_, _, kvs)        = fromMaybe "html" $ lookup "style" kvs
    rawBlock (attrs, content) = B.rawBlock (format attrs) $ chop content

-- <center> tag is ignored
centerTag :: PandocMonad m => MuseParser m (F Blocks)
centerTag = snd <$> parseHtmlContent "center"

-- <right> tag is ignored
rightTag :: PandocMonad m => MuseParser m (F Blocks)
rightTag = snd <$> parseHtmlContent "right"

quoteTag :: PandocMonad m => MuseParser m (F Blocks)
quoteTag = fmap B.blockQuote . snd <$> parseHtmlContent "quote"

-- <div> tag is supported by Emacs Muse, but not Amusewiki 2.025
divTag :: PandocMonad m => MuseParser m (F Blocks)
divTag = do
  (attrs, content) <- parseHtmlContent "div"
  return $ B.divWith attrs <$> content

verseLine :: PandocMonad m => MuseParser m (F Inlines)
verseLine = do
  indent <- (B.str <$> many1 (char ' ' >> pure '\160')) <|> pure mempty
  rest <- manyTill (choice inlineList) newline
  return $ trimInlinesF $ mconcat (pure indent : rest)

verseLines :: PandocMonad m => MuseParser m (F Blocks)
verseLines = do
  lns <- many verseLine
  return $ B.lineBlock <$> sequence lns

verseTag :: PandocMonad m => MuseParser m (F Blocks)
verseTag = do
  (_, content) <- htmlBlock "verse"
  parseFromString verseLines (intercalate "\n" $ dropSpacePrefix $ splitOn "\n" $ lchop content)

commentTag :: PandocMonad m => MuseParser m (F Blocks)
commentTag = htmlBlock "comment" >> return mempty

-- Indented paragraph is either center, right or quote
paraUntil :: PandocMonad m
          => MuseParser m a
          -> MuseParser m (F Blocks, a)
paraUntil end = do
  state <- getState
  guard $ not $ museInPara state
  setState $ state{ museInPara = True }
  (l, e) <- someUntil inline $ try (manyTill spaceChar eol >> end)
  updateState (\st -> st { museInPara = False })
  return (fmap B.para $ trimInlinesF $ mconcat l, e)

noteMarker :: PandocMonad m => MuseParser m String
noteMarker = try $ do
  char '['
  first <- oneOf "123456789"
  rest <- manyTill digit (char ']')
  return $ first:rest

-- Amusewiki version of note
-- Parsing is similar to list item, except that note marker is used instead of list marker
amuseNoteBlockUntil :: PandocMonad m
                    => MuseParser m a
                    -> MuseParser m (F Blocks, a)
amuseNoteBlockUntil end = try $ do
  guardEnabled Ext_amuse
  pos <- getPosition
  ref <- noteMarker <* spaceChar
  updateState (\st -> st { museInPara = False })
  (content, e) <- listItemContentsUntil (sourceColumn pos) (fail "x") end
  oldnotes <- museNotes <$> getState
  case M.lookup ref oldnotes of
    Just _  -> logMessage $ DuplicateNoteReference ref pos
    Nothing -> return ()
  updateState $ \s -> s{ museNotes = M.insert ref (pos, content) oldnotes }
  return (mempty, e)

-- Emacs version of note
-- Notes are allowed only at the end of text, no indentation is required.
emacsNoteBlock :: PandocMonad m => MuseParser m (F Blocks)
emacsNoteBlock = try $ do
  guardDisabled Ext_amuse
  pos <- getPosition
  ref <- noteMarker <* skipSpaces
  content <- mconcat <$> blocksTillNote
  oldnotes <- museNotes <$> getState
  case M.lookup ref oldnotes of
    Just _  -> logMessage $ DuplicateNoteReference ref pos
    Nothing -> return ()
  updateState $ \s -> s{ museNotes = M.insert ref (pos, content) oldnotes }
  return mempty
  where
    blocksTillNote =
      many1Till parseBlock (eof <|> () <$ lookAhead noteMarker)

--
-- Verse markup
--

lineVerseLine :: PandocMonad m => MuseParser m (F Inlines)
lineVerseLine = try $ do
  string "> "
  indent <- B.str <$> many (char ' ' >> pure '\160')
  rest <- manyTill (choice inlineList) eol
  return $ trimInlinesF $ mconcat (pure indent : rest)

blanklineVerseLine :: PandocMonad m => MuseParser m (F Inlines)
blanklineVerseLine = try $ do
  char '>'
  blankline
  pure mempty

lineBlock :: PandocMonad m => MuseParser m (F Blocks)
lineBlock = try $ do
  col <- sourceColumn <$> getPosition
  lns <- (blanklineVerseLine <|> lineVerseLine) `sepBy1'` try (indentWith (col - 1))
  return $ B.lineBlock <$> sequence lns

--
-- lists
--

bulletListItemsUntil :: PandocMonad m
                     => Int
                     -> MuseParser m a
                     -> MuseParser m ([F Blocks], a)
bulletListItemsUntil indent end = try $ do
  char '-'
  void spaceChar <|> lookAhead eol
  updateState (\st -> st { museInPara = False })
  (x, e) <- listItemContentsUntil (indent + 2) (Right <$> try (optional blankline >> indentWith indent >> bulletListItemsUntil indent end)) (Left <$> end)
  case e of
    Left ee -> return ([x], ee)
    Right (xs, ee) -> return (x:xs, ee)

bulletListUntil :: PandocMonad m
                => MuseParser m a
                -> MuseParser m (F Blocks, a)
bulletListUntil end = try $ do
  many spaceChar
  pos <- getPosition
  let indent = sourceColumn pos - 1
  guard $ indent /= 0
  (items, e) <- bulletListItemsUntil indent end
  return (B.bulletList <$> sequence items, e)

-- | Parses an ordered list marker and returns list attributes.
anyMuseOrderedListMarker :: PandocMonad m => MuseParser m ListAttributes
anyMuseOrderedListMarker = do
  (style, start) <- decimal <|> lowerRoman <|> upperRoman <|> lowerAlpha <|> upperAlpha
  char '.'
  return (start, style, Period)

museOrderedListMarker :: PandocMonad m
                      => ListNumberStyle
                      -> MuseParser m Int
museOrderedListMarker style = do
  (_, start) <- case style of
                  Decimal    -> decimal
                  UpperRoman -> upperRoman
                  LowerRoman -> lowerRoman
                  UpperAlpha -> upperAlpha
                  LowerAlpha -> lowerAlpha
                  _          -> fail "Unhandled case"
  char '.'
  return start

orderedListItemsUntil :: PandocMonad m
                      => Int
                      -> ListNumberStyle
                      -> MuseParser m a
                      -> MuseParser m ([F Blocks], a)
orderedListItemsUntil indent style end =
  continuation
  where
    continuation = try $ do
      pos <- getPosition
      void spaceChar <|> lookAhead eol
      updateState (\st -> st { museInPara = False })
      (x, e) <- listItemContentsUntil (sourceColumn pos) (Right <$> try (optionMaybe blankline >> indentWith indent >> museOrderedListMarker style >> continuation)) (Left <$> end)
      case e of
        Left ee -> return ([x], ee)
        Right (xs, ee) -> return (x:xs, ee)

orderedListUntil :: PandocMonad m
                 => MuseParser m a
                 -> MuseParser m (F Blocks, a)
orderedListUntil end = try $ do
  many spaceChar
  pos <- getPosition
  let indent = sourceColumn pos - 1
  guard $ indent /= 0
  p@(_, style, _) <- anyMuseOrderedListMarker
  guard $ style `elem` [Decimal, LowerAlpha, UpperAlpha, LowerRoman, UpperRoman]
  (items, e) <- orderedListItemsUntil indent style end
  return (B.orderedListWith p <$> sequence items, e)

descriptionsUntil :: PandocMonad m
                  => Int
                  -> MuseParser m a
                  -> MuseParser m ([F Blocks], a)
descriptionsUntil indent end = do
  void spaceChar <|> lookAhead eol
  updateState (\st -> st { museInPara = False })
  (x, e) <- listItemContentsUntil indent (Right <$> try (optional blankline >> indentWith indent >> manyTill spaceChar (string "::") >> descriptionsUntil indent end)) (Left <$> end)
  case e of
    Right (xs, ee) -> return (x:xs, ee)
    Left ee -> return ([x], ee)

definitionListItemsUntil :: PandocMonad m
                         => Int
                         -> MuseParser m a
                         -> MuseParser m ([F (Inlines, [Blocks])], a)
definitionListItemsUntil indent end =
  continuation
  where
    continuation = try $ do
      pos <- getPosition
      term <- trimInlinesF . mconcat <$> manyTill (choice inlineList) (try $ string "::")
      (x, e) <- descriptionsUntil (sourceColumn pos) ((Right <$> try (optional blankline >> indentWith indent >> continuation)) <|> (Left <$> end))
      let xx = do
            term' <- term
            x' <- sequence x
            return (term', x')
      case e of
        Left ee -> return ([xx], ee)
        Right (xs, ee) -> return (xx:xs, ee)

definitionListUntil :: PandocMonad m
                    => MuseParser m a
                    -> MuseParser m (F Blocks, a)
definitionListUntil end = try $ do
  many spaceChar
  pos <- getPosition
  let indent = sourceColumn pos - 1
  guardDisabled Ext_amuse <|> guard (indent /= 0) -- Initial space is required by Amusewiki, but not Emacs Muse
  (items, e) <- definitionListItemsUntil indent end
  return (B.definitionList <$> sequence items, e)

anyListUntil :: PandocMonad m
             => MuseParser m a
             -> MuseParser m (F Blocks, a)
anyListUntil end =
  bulletListUntil end <|> orderedListUntil end <|> definitionListUntil end

--
-- tables
--

data MuseTable = MuseTable
  { museTableCaption :: Inlines
  , museTableHeaders :: [[Blocks]]
  , museTableRows    :: [[Blocks]]
  , museTableFooters :: [[Blocks]]
  }

data MuseTableElement = MuseHeaderRow (F [Blocks])
                      | MuseBodyRow   (F [Blocks])
                      | MuseFooterRow (F [Blocks])
                      | MuseCaption (F Inlines)

museToPandocTable :: MuseTable -> Blocks
museToPandocTable (MuseTable caption headers body footers) =
  B.table caption attrs headRow rows
  where ncol = maximum (0 : map length (headers ++ body ++ footers))
        attrs = replicate ncol (AlignDefault, 0.0)
        headRow = if null headers then [] else head headers
        rows = (if null headers then [] else tail headers) ++ body ++ footers

museAppendElement :: MuseTable
                  -> MuseTableElement
                  -> F MuseTable
museAppendElement tbl element =
  case element of
    MuseHeaderRow row -> do
      row' <- row
      return tbl{ museTableHeaders = museTableHeaders tbl ++ [row'] }
    MuseBodyRow row -> do
      row' <- row
      return tbl{ museTableRows = museTableRows tbl ++ [row'] }
    MuseFooterRow row-> do
      row' <- row
      return tbl{ museTableFooters = museTableFooters tbl ++ [row'] }
    MuseCaption inlines -> do
      inlines' <- inlines
      return tbl{ museTableCaption = inlines' }

tableCell :: PandocMonad m => MuseParser m (F Blocks)
tableCell = try $ fmap B.plain . trimInlinesF . mconcat <$> manyTill inline (lookAhead cellEnd)
  where cellEnd = try $ void (many1 spaceChar >> char '|') <|> eol

tableElements :: PandocMonad m => MuseParser m [MuseTableElement]
tableElements = tableParseElement `sepEndBy1` eol

elementsToTable :: [MuseTableElement] -> F MuseTable
elementsToTable = foldM museAppendElement emptyTable
  where emptyTable = MuseTable mempty mempty mempty mempty

table :: PandocMonad m => MuseParser m (F Blocks)
table = try $ do
  rows <- tableElements
  let tbl = elementsToTable rows
  let pandocTbl = museToPandocTable <$> tbl :: F Blocks
  return pandocTbl

tableParseElement :: PandocMonad m => MuseParser m MuseTableElement
tableParseElement = tableParseHeader
                <|> tableParseBody
                <|> tableParseFooter
                <|> tableParseCaption

tableParseRow :: PandocMonad m => Int -> MuseParser m (F [Blocks])
tableParseRow n = try $ do
  fields <- tableCell `sepBy2` fieldSep
  return $ sequence fields
    where p `sepBy2` sep = (:) <$> p <*> many1 (sep >> p)
          fieldSep = many1 spaceChar >> count n (char '|') >> (void (many1 spaceChar) <|> void (lookAhead newline))

tableParseHeader :: PandocMonad m => MuseParser m MuseTableElement
tableParseHeader = MuseHeaderRow <$> tableParseRow 2

tableParseBody :: PandocMonad m => MuseParser m MuseTableElement
tableParseBody = MuseBodyRow <$> tableParseRow 1

tableParseFooter :: PandocMonad m => MuseParser m MuseTableElement
tableParseFooter = MuseFooterRow <$> tableParseRow 3

tableParseCaption :: PandocMonad m => MuseParser m MuseTableElement
tableParseCaption = try $ do
  many spaceChar
  string "|+"
  MuseCaption <$> (trimInlinesF . mconcat <$> many1Till inline (string "+|"))

--
-- inline parsers
--

inlineList :: PandocMonad m => [MuseParser m (F Inlines)]
inlineList = [ whitespace
             , br
             , anchor
             , footnote
             , strong
             , strongTag
             , emph
             , emphTag
             , underlined
             , superscriptTag
             , subscriptTag
             , strikeoutTag
             , verbatimTag
             , nbsp
             , link
             , code
             , codeTag
             , inlineLiteralTag
             , str
             , symbol
             ]

inline :: PandocMonad m => MuseParser m (F Inlines)
inline = endline <|> choice inlineList <?> "inline"

endline :: PandocMonad m => MuseParser m (F Inlines)
endline = try $ do
  newline
  notFollowedBy blankline
  returnF B.softbreak

parseAnchor :: PandocMonad m => MuseParser m String
parseAnchor = try $ do
  getPosition >>= \pos -> guard (sourceColumn pos == 1)
  char '#'
  first <- letter
  rest <- many (letter <|> digit)
  skipMany spaceChar <|> void newline
  return $ first:rest

anchor :: PandocMonad m => MuseParser m (F Inlines)
anchor = try $ do
  anchorId <- parseAnchor
  return $ return $ B.spanWith (anchorId, [], []) mempty

footnote :: PandocMonad m => MuseParser m (F Inlines)
footnote = try $ do
  ref <- noteMarker
  return $ do
    notes <- asksF museNotes
    case M.lookup ref notes of
      Nothing -> return $ B.str $ "[" ++ ref ++ "]"
      Just (_pos, contents) -> do
        st <- askF
        let contents' = runF contents st { museNotes = M.empty }
        return $ B.note contents'

whitespace :: PandocMonad m => MuseParser m (F Inlines)
whitespace = try $ do
  skipMany1 spaceChar
  return $ return B.space

br :: PandocMonad m => MuseParser m (F Inlines)
br = try $ do
  string "<br>"
  return $ return B.linebreak

emphasisBetween :: (PandocMonad m, Show a) => MuseParser m a -> MuseParser m (F Inlines)
emphasisBetween c = try $ enclosedInlines c c

enclosedInlines :: (PandocMonad m, Show a, Show b)
                => MuseParser m a
                -> MuseParser m b
                -> MuseParser m (F Inlines)
enclosedInlines start end = try $
  trimInlinesF . mconcat <$> (enclosed (atStart start) end inline <* notFollowedBy (satisfy isLetter))

inlineTag :: PandocMonad m
          => (Inlines -> Inlines)
          -> String
          -> MuseParser m (F Inlines)
inlineTag f tag = try $ do
  htmlTag (~== TagOpen tag [])
  res <- manyTill inline (void $ htmlTag (~== TagClose tag))
  return $ f <$> mconcat res

strongTag :: PandocMonad m => MuseParser m (F Inlines)
strongTag = inlineTag B.strong "strong"

strong :: PandocMonad m => MuseParser m (F Inlines)
strong = fmap B.strong <$> emphasisBetween (string "**")

emph :: PandocMonad m => MuseParser m (F Inlines)
emph = fmap B.emph <$> emphasisBetween (char '*')

underlined :: PandocMonad m => MuseParser m (F Inlines)
underlined = do
  guardDisabled Ext_amuse -- Supported only by Emacs Muse
  fmap underlineSpan <$> emphasisBetween (char '_')

emphTag :: PandocMonad m => MuseParser m (F Inlines)
emphTag = inlineTag B.emph "em"

superscriptTag :: PandocMonad m => MuseParser m (F Inlines)
superscriptTag = inlineTag B.superscript "sup"

subscriptTag :: PandocMonad m => MuseParser m (F Inlines)
subscriptTag = inlineTag B.subscript "sub"

strikeoutTag :: PandocMonad m => MuseParser m (F Inlines)
strikeoutTag = inlineTag B.strikeout "del"

verbatimTag :: PandocMonad m => MuseParser m (F Inlines)
verbatimTag = return . B.text . snd <$> htmlElement "verbatim"

nbsp :: PandocMonad m => MuseParser m (F Inlines)
nbsp = try $ do
  string "~~"
  return $ return $ B.str "\160"

code :: PandocMonad m => MuseParser m (F Inlines)
code = try $ do
  atStart $ char '='
  contents <- many1Till (noneOf "\n\r" <|> (newline <* notFollowedBy newline)) $ char '='
  guard $ not $ null contents
  guard $ head contents `notElem` " \t\n"
  guard $ last contents `notElem` " \t\n"
  notFollowedBy $ satisfy isLetter
  return $ return $ B.code contents

codeTag :: PandocMonad m => MuseParser m (F Inlines)
codeTag = do
  (attrs, content) <- htmlElement "code"
  return $ return $ B.codeWith attrs content

inlineLiteralTag :: PandocMonad m => MuseParser m (F Inlines)
inlineLiteralTag = do
  guardDisabled Ext_amuse -- Text::Amuse does not support <literal>
  (return . rawInline) <$> htmlElement "literal"
  where
    -- FIXME: Emacs Muse inserts <literal> without style into all output formats, but we assume HTML
    format (_, _, kvs)        = fromMaybe "html" $ lookup "style" kvs
    rawInline (attrs, content) = B.rawInline (format attrs) content

str :: PandocMonad m => MuseParser m (F Inlines)
str = do
  result <- many1 alphaNum
  updateLastStrPos
  return $ return $ B.str result

symbol :: PandocMonad m => MuseParser m (F Inlines)
symbol = return . B.str <$> count 1 nonspaceChar

link :: PandocMonad m => MuseParser m (F Inlines)
link = try $ do
  st <- getState
  guard $ not $ museInLink st
  setState $ st{ museInLink = True }
  (url, title, content) <- linkText
  updateState (\state -> state { museInLink = False })
  return $ case stripPrefix "URL:" url of
             Nothing -> if isImageUrl url
                          then B.image url title <$> fromMaybe (return mempty) content
                          else B.link url title <$> fromMaybe (return $ B.str url) content
             Just url' -> B.link url' title <$> fromMaybe (return $ B.str url') content
    where -- Taken from muse-image-regexp defined in Emacs Muse file lisp/muse-regexps.el
          imageExtensions = [".eps", ".gif", ".jpg", ".jpeg", ".pbm", ".png", ".tiff", ".xbm", ".xpm"]
          isImageUrl = (`elem` imageExtensions) . takeExtension

linkContent :: PandocMonad m => MuseParser m (F Inlines)
linkContent = do
  char '['
  trimInlinesF . mconcat <$> many1Till inline (string "]")

linkText :: PandocMonad m => MuseParser m (String, String, Maybe (F Inlines))
linkText = do
  string "[["
  url <- many1Till anyChar $ char ']'
  content <- optionMaybe linkContent
  char ']'
  return (url, "", content)