aboutsummaryrefslogtreecommitdiff
path: root/src/Text/Pandoc/Readers/RST.hs
blob: f181d523a16f6eb43f7241eb3c6e5312ccb121b6 (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
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE FlexibleContexts #-}
{-
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.RST
   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 from reStructuredText to 'Pandoc' document.
-}
module Text.Pandoc.Readers.RST (
                                readRST,
                                readRSTWithWarnings
                               ) where
import Text.Pandoc.Definition
import Text.Pandoc.Builder (setMeta, fromList)
import Text.Pandoc.Shared
import Text.Pandoc.Parsing
import Text.Pandoc.Options
import Control.Monad ( when, liftM, guard, mzero )
import Data.List ( findIndex, intersperse, intercalate,
                   transpose, sort, deleteFirstsBy, isSuffixOf , nub, union)
import Data.Maybe (fromMaybe)
import qualified Data.Map as M
import Text.Printf ( printf )
import Text.Pandoc.Builder (Inlines, Blocks, trimInlines)
import qualified Text.Pandoc.Builder as B
import Data.Sequence (viewr, ViewR(..))
import Data.Char (toLower, isHexDigit, isSpace)
import Data.Monoid ((<>))
import Text.Pandoc.Error

-- | Parse reStructuredText string and return Pandoc document.
readRST :: ReaderOptions -- ^ Reader options
        -> String        -- ^ String to parse (assuming @'\n'@ line endings)
        -> Either PandocError Pandoc
readRST opts s = (readWith parseRST) def{ stateOptions = opts } (s ++ "\n\n")

readRSTWithWarnings :: ReaderOptions -> String -> Either PandocError (Pandoc, [String])
readRSTWithWarnings opts s = (readWithWarnings parseRST) def{ stateOptions = opts } (s ++ "\n\n")

type RSTParser = Parser [Char] ParserState

--
-- Constants and data structure definitions
---

bulletListMarkers :: [Char]
bulletListMarkers = "*+-"

underlineChars :: [Char]
underlineChars = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~"

-- treat these as potentially non-text when parsing inline:
specialChars :: [Char]
specialChars = "\\`|*_<>$:/[]{}()-.\"'\8216\8217\8220\8221"

--
-- parsing documents
--

isHeader :: Int -> Block -> Bool
isHeader n (Header x _ _) = x == n
isHeader _ _              = False

-- | Promote all headers in a list of blocks.  (Part of
-- title transformation for RST.)
promoteHeaders :: Int -> [Block] -> [Block]
promoteHeaders num ((Header level attr text):rest) =
    (Header (level - num) attr text):(promoteHeaders num rest)
promoteHeaders num (other:rest) = other:(promoteHeaders num rest)
promoteHeaders _   [] = []

-- | If list of blocks starts with a header (or a header and subheader)
-- of level that are not found elsewhere, return it as a title and
-- promote all the other headers.  Also process a definition list right
-- after the title block as metadata.
titleTransform :: ([Block], Meta)  -- ^ list of blocks, metadata
               -> ([Block], Meta)  -- ^ modified list of blocks, metadata
titleTransform (bs, meta) =
  let (bs', meta') =
       case bs of
          ((Header 1 _ head1):(Header 2 _ head2):rest)
           | not (any (isHeader 1) rest || any (isHeader 2) rest) -> -- tit/sub
            (promoteHeaders 2 rest, setMeta "title" (fromList head1) $
              setMeta "subtitle" (fromList head2) meta)
          ((Header 1 _ head1):rest)
           | not (any (isHeader 1) rest) -> -- title only
            (promoteHeaders 1 rest,
                setMeta "title" (fromList head1) meta)
          _ -> (bs, meta)
  in   case bs' of
          (DefinitionList ds : rest) ->
            (rest, metaFromDefList ds meta')
          _ -> (bs', meta')

metaFromDefList :: [([Inline], [[Block]])] -> Meta -> Meta
metaFromDefList ds meta = adjustAuthors $ foldr f meta ds
 where f (k,v) = setMeta (map toLower $ stringify k) (mconcat $ map fromList v)
       adjustAuthors (Meta metamap) = Meta $ M.adjust splitAuthors "author"
                                           $ M.adjust toPlain "date"
                                           $ M.adjust toPlain "title"
                                           $ M.mapKeys (\k -> if k == "authors" then "author" else k)
                                           $ metamap
       toPlain (MetaBlocks [Para xs]) = MetaInlines xs
       toPlain x                      = x
       splitAuthors (MetaBlocks [Para xs])
                                      = MetaList $ map MetaInlines
                                                 $ splitAuthors' xs
       splitAuthors x                 = x
       splitAuthors'                  = map normalizeSpaces .
                                         splitOnSemi . concatMap factorSemi
       splitOnSemi                    = splitBy (==Str ";")
       factorSemi (Str [])            = []
       factorSemi (Str s)             = case break (==';') s of
                                             (xs,[]) -> [Str xs]
                                             (xs,';':ys) -> Str xs : Str ";" :
                                                factorSemi (Str ys)
                                             (xs,ys) -> Str xs :
                                                factorSemi (Str ys)
       factorSemi x                   = [x]

parseRST :: RSTParser Pandoc
parseRST = do
  optional blanklines -- skip blank lines at beginning of file
  startPos <- getPosition
  -- go through once just to get list of reference keys and notes
  -- docMinusKeys is the raw document with blanks where the keys were...
  docMinusKeys <- concat <$>
                  manyTill (referenceKey <|> noteBlock <|> lineClump) eof
  setInput docMinusKeys
  setPosition startPos
  st' <- getState
  let reversedNotes = stateNotes st'
  updateState $ \s -> s { stateNotes = reverse reversedNotes }
  -- now parse it for real...
  blocks <- B.toList <$> parseBlocks
  standalone <- getOption readerStandalone
  state <- getState
  let meta = stateMeta state
  let (blocks', meta') = if standalone
                            then titleTransform (blocks, meta)
                            else (blocks, meta)
  return $ Pandoc meta' blocks'

--
-- parsing blocks
--

parseBlocks :: RSTParser Blocks
parseBlocks = mconcat <$> manyTill block eof

block :: RSTParser Blocks
block = choice [ codeBlock
               , blockQuote
               , fieldList
               , directive
               , comment
               , header
               , hrule
               , lineBlock     -- must go before definitionList
               , table
               , list
               , lhsCodeBlock
               , para
               , mempty <$ blanklines
               ] <?> "block"

--
-- field list
--

rawFieldListItem :: Int -> RSTParser (String, String)
rawFieldListItem minIndent = try $ do
  indent <- length <$> many (char ' ')
  guard $ indent >= minIndent
  char ':'
  name <- many1Till (noneOf "\n") (char ':')
  (() <$ lookAhead newline) <|> skipMany1 spaceChar
  first <- anyLine
  rest <- option "" $ try $ do lookAhead (count indent (char ' ') >> spaceChar)
                               indentedBlock
  let raw = (if null first then "" else (first ++ "\n")) ++ rest ++ "\n"
  return (name, raw)

fieldListItem :: Int -> RSTParser (Inlines, [Blocks])
fieldListItem minIndent = try $ do
  (name, raw) <- rawFieldListItem minIndent
  term <- parseInlineFromString name
  contents <- parseFromString parseBlocks raw
  optional blanklines
  return (term, [contents])

fieldList :: RSTParser Blocks
fieldList = try $ do
  indent <- length <$> lookAhead (many spaceChar)
  items <- many1 $ fieldListItem indent
  case items of
     []     -> return mempty
     items' -> return $ B.definitionList items'

--
-- line block
--

lineBlock :: RSTParser Blocks
lineBlock = try $ do
  lines' <- lineBlockLines
  lines'' <- mapM parseInlineFromString lines'
  return $ B.para (mconcat $ intersperse B.linebreak lines'')

--
-- paragraph block
--

-- note: paragraph can end in a :: starting a code block
para :: RSTParser Blocks
para = try $ do
  result <- trimInlines . mconcat <$> many1 inline
  option (B.plain result) $ try $ do
    newline
    blanklines
    case viewr (B.unMany result) of
         ys :> (Str xs) | "::" `isSuffixOf` xs -> do
              raw <- option mempty codeBlockBody
              return $ B.para (B.Many ys <> B.str (take (length xs - 1) xs))
                         <> raw
         _ -> return (B.para result)

plain :: RSTParser Blocks
plain = B.plain . trimInlines . mconcat <$> many1 inline

--
-- header blocks
--

header :: RSTParser Blocks
header = doubleHeader <|> singleHeader <?> "header"

-- a header with lines on top and bottom
doubleHeader :: RSTParser Blocks
doubleHeader = try $ do
  c <- oneOf underlineChars
  rest <- many (char c)  -- the top line
  let lenTop = length (c:rest)
  skipSpaces
  newline
  txt <- trimInlines . mconcat <$> many1 (notFollowedBy blankline >> inline)
  pos <- getPosition
  let len = (sourceColumn pos) - 1
  if (len > lenTop) then fail "title longer than border" else return ()
  blankline              -- spaces and newline
  count lenTop (char c)  -- the bottom line
  blanklines
  -- check to see if we've had this kind of header before.
  -- if so, get appropriate level.  if not, add to list.
  state <- getState
  let headerTable = stateHeaderTable state
  let (headerTable',level) = case findIndex (== DoubleHeader c) headerTable of
        Just ind -> (headerTable, ind + 1)
        Nothing -> (headerTable ++ [DoubleHeader c], (length headerTable) + 1)
  setState (state { stateHeaderTable = headerTable' })
  attr <- registerHeader nullAttr txt
  return $ B.headerWith attr level txt

-- a header with line on the bottom only
singleHeader :: RSTParser Blocks
singleHeader = try $ do
  notFollowedBy' whitespace
  txt <- trimInlines . mconcat <$> many1 (do {notFollowedBy blankline; inline})
  pos <- getPosition
  let len = (sourceColumn pos) - 1
  blankline
  c <- oneOf underlineChars
  count (len - 1) (char c)
  many (char c)
  blanklines
  state <- getState
  let headerTable = stateHeaderTable state
  let (headerTable',level) = case findIndex (== SingleHeader c) headerTable of
        Just ind -> (headerTable, ind + 1)
        Nothing -> (headerTable ++ [SingleHeader c], (length headerTable) + 1)
  setState (state { stateHeaderTable = headerTable' })
  attr <- registerHeader nullAttr txt
  return $ B.headerWith attr level txt

--
-- hrule block
--

hrule :: Parser [Char] st Blocks
hrule = try $ do
  chr <- oneOf underlineChars
  count 3 (char chr)
  skipMany (char chr)
  blankline
  blanklines
  return B.horizontalRule

--
-- code blocks
--

-- read a line indented by a given string
indentedLine :: String -> Parser [Char] st [Char]
indentedLine indents = try $ do
  string indents
  anyLine

-- one or more indented lines, possibly separated by blank lines.
-- any amount of indentation will work.
indentedBlock :: Parser [Char] st [Char]
indentedBlock = try $ do
  indents <- lookAhead $ many1 spaceChar
  lns <- many1 $ try $ do b <- option "" blanklines
                          l <- indentedLine indents
                          return (b ++ l)
  optional blanklines
  return $ unlines lns

quotedBlock :: Parser [Char] st [Char]
quotedBlock = try $ do
    quote <- lookAhead $ oneOf "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~"
    lns <- many1 $ lookAhead (char quote) >> anyLine
    optional blanklines
    return $ unlines lns

codeBlockStart :: Parser [Char] st Char
codeBlockStart = string "::" >> blankline >> blankline

codeBlock :: Parser [Char] st Blocks
codeBlock = try $ codeBlockStart >> codeBlockBody

codeBlockBody :: Parser [Char] st Blocks
codeBlockBody = try $ B.codeBlock . stripTrailingNewlines <$>
                (indentedBlock <|> quotedBlock)

lhsCodeBlock :: RSTParser Blocks
lhsCodeBlock = try $ do
  getPosition >>= guard . (==1) . sourceColumn
  guardEnabled Ext_literate_haskell
  optional codeBlockStart
  lns <- latexCodeBlock <|> birdCodeBlock
  blanklines
  return $ B.codeBlockWith ("", ["sourceCode", "literate", "haskell"], [])
         $ intercalate "\n" lns

latexCodeBlock :: Parser [Char] st [[Char]]
latexCodeBlock = try $ do
  try (latexBlockLine "\\begin{code}")
  many1Till anyLine (try $ latexBlockLine "\\end{code}")
 where
  latexBlockLine s = skipMany spaceChar >> string s >> blankline

birdCodeBlock :: Parser [Char] st [[Char]]
birdCodeBlock = filterSpace <$> many1 birdTrackLine
  where filterSpace lns =
            -- if (as is normal) there is always a space after >, drop it
            if all (\ln -> null ln || take 1 ln == " ") lns
               then map (drop 1) lns
               else lns

birdTrackLine :: Parser [Char] st [Char]
birdTrackLine = char '>' >> anyLine

--
-- block quotes
--

blockQuote :: RSTParser Blocks
blockQuote = do
  raw <- indentedBlock
  -- parse the extracted block, which may contain various block elements:
  contents <- parseFromString parseBlocks $ raw ++ "\n\n"
  return $ B.blockQuote contents

--
-- list blocks
--

list :: RSTParser Blocks
list = choice [ bulletList, orderedList, definitionList ] <?> "list"

definitionListItem :: RSTParser (Inlines, [Blocks])
definitionListItem = try $ do
  -- avoid capturing a directive or comment
  notFollowedBy (try $ char '.' >> char '.')
  term <- trimInlines . mconcat <$> many1Till inline endline
  raw <- indentedBlock
  -- parse the extracted block, which may contain various block elements:
  contents <- parseFromString parseBlocks $ raw ++ "\n"
  return (term, [contents])

definitionList :: RSTParser Blocks
definitionList = B.definitionList <$> many1 definitionListItem

-- parses bullet list start and returns its length (inc. following whitespace)
bulletListStart :: Parser [Char] st Int
bulletListStart = try $ do
  notFollowedBy' hrule  -- because hrules start out just like lists
  marker <- oneOf bulletListMarkers
  white <- many1 spaceChar
  return $ length (marker:white)

-- parses ordered list start and returns its length (inc following whitespace)
orderedListStart :: ListNumberStyle
                 -> ListNumberDelim
                 -> RSTParser Int
orderedListStart style delim = try $ do
  (_, markerLen) <- withHorizDisplacement (orderedListMarker style delim)
  white <- many1 spaceChar
  return $ markerLen + length white

-- parse a line of a list item
listLine :: Int -> RSTParser [Char]
listLine markerLength = try $ do
  notFollowedBy blankline
  indentWith markerLength
  line <- anyLine
  return $ line ++ "\n"

-- indent by specified number of spaces (or equiv. tabs)
indentWith :: Int -> RSTParser [Char]
indentWith num = do
  tabStop <- getOption readerTabStop
  if (num < tabStop)
     then count num  (char ' ')
     else choice [ try (count num (char ' ')),
                   (try (char '\t' >> count (num - tabStop) (char ' '))) ]

-- parse raw text for one list item, excluding start marker and continuations
rawListItem :: RSTParser Int
            -> RSTParser (Int, [Char])
rawListItem start = try $ do
  markerLength <- start
  firstLine <- anyLine
  restLines <- many (listLine markerLength)
  return (markerLength, (firstLine ++ "\n" ++ (concat restLines)))

-- continuation of a list item - indented and separated by blankline or
-- (in compact lists) endline.
-- Note: nested lists are parsed as continuations.
listContinuation :: Int -> RSTParser [Char]
listContinuation markerLength = try $ do
  blanks <- many1 blankline
  result <- many1 (listLine markerLength)
  return $ blanks ++ concat result

listItem :: RSTParser Int
         -> RSTParser Blocks
listItem start = try $ do
  (markerLength, first) <- rawListItem start
  rest <- many (listContinuation markerLength)
  blanks <- choice [ try (many blankline <* lookAhead start),
                     many1 blankline ]  -- whole list must end with blank.
  -- parsing with ListItemState forces markers at beginning of lines to
  -- count as list item markers, even if not separated by blank space.
  -- see definition of "endline"
  state <- getState
  let oldContext = stateParserContext state
  setState $ state {stateParserContext = ListItemState}
  -- parse the extracted block, which may itself contain block elements
  parsed <- parseFromString parseBlocks $ concat (first:rest) ++ blanks
  updateState (\st -> st {stateParserContext = oldContext})
  return $ case B.toList parsed of
                [Para xs] -> B.singleton $ Plain xs
                [Para xs, BulletList ys] -> B.fromList [Plain xs, BulletList ys]
                [Para xs, OrderedList s ys] -> B.fromList [Plain xs, OrderedList s ys]
                [Para xs, DefinitionList ys] -> B.fromList [Plain xs, DefinitionList ys]
                _         -> parsed

orderedList :: RSTParser Blocks
orderedList = try $ do
  (start, style, delim) <- lookAhead (anyOrderedListMarker <* spaceChar)
  items <- many1 (listItem (orderedListStart style delim))
  let items' = compactify' items
  return $ B.orderedListWith (start, style, delim) items'

bulletList :: RSTParser Blocks
bulletList = B.bulletList . compactify' <$> many1 (listItem bulletListStart)

--
-- directive (e.g. comment, container, compound-paragraph)
--

comment :: RSTParser Blocks
comment = try $ do
  string ".."
  skipMany1 spaceChar <|> (() <$ lookAhead newline)
  notFollowedBy' directiveLabel
  manyTill anyChar blanklines
  optional indentedBlock
  return mempty

directiveLabel :: RSTParser String
directiveLabel = map toLower
  <$> many1Till (letter <|> char '-') (try $ string "::")

directive :: RSTParser Blocks
directive = try $ do
  string ".."
  directive'

-- TODO: line-block, parsed-literal, table, csv-table, list-table
-- date
-- include
-- title
directive' :: RSTParser Blocks
directive' = do
  skipMany1 spaceChar
  label <- directiveLabel
  skipMany spaceChar
  top <- many $ satisfy (/='\n')
             <|> try (char '\n' <*
                      notFollowedBy' (rawFieldListItem 3) <*
                      count 3 (char ' ') <*
                      notFollowedBy blankline)
  newline
  fields <- many $ rawFieldListItem 3
  body <- option "" $ try $ blanklines >> indentedBlock
  optional blanklines
  let body' = body ++ "\n\n"
      imgAttr cl = ("", classes, getAtt "width" ++ getAtt "height")
        where
          classes = words $ maybe "" trim $ lookup cl fields
          getAtt k = case lookup k fields of
                       Just v  -> [(k, filter (not . isSpace) v)]
                       Nothing -> []
  case label of
        "raw" -> return $ B.rawBlock (trim top) (stripTrailingNewlines body)
        "role" -> addNewRole top $ map (\(k,v) -> (k, trim v)) fields
        "container" -> parseFromString parseBlocks body'
        "replace" -> B.para <$>  -- consumed by substKey
                   parseInlineFromString (trim top)
        "unicode" -> B.para <$>  -- consumed by substKey
                   parseInlineFromString (trim $ unicodeTransform top)
        "compound" -> parseFromString parseBlocks body'
        "pull-quote" -> B.blockQuote <$> parseFromString parseBlocks body'
        "epigraph" -> B.blockQuote <$> parseFromString parseBlocks body'
        "highlights" -> B.blockQuote <$> parseFromString parseBlocks body'
        "rubric" -> B.para . B.strong <$> parseInlineFromString top
        _ | label `elem` ["attention","caution","danger","error","hint",
                          "important","note","tip","warning"] ->
           do bod <- parseFromString parseBlocks $ top ++ "\n\n" ++ body'
              return $ B.divWith ("",["admonition", label],[]) bod
        "admonition" ->
           do bod <- parseFromString parseBlocks $ top ++ "\n\n" ++ body'
              return $ B.divWith ("",["admonition"],[]) bod
        "sidebar" ->
           do let subtit = maybe "" trim $ lookup "subtitle" fields
              tit <- B.para . B.strong <$> parseInlineFromString
                          (trim top ++ if null subtit
                                          then ""
                                          else (":  " ++ subtit))
              bod <- parseFromString parseBlocks body'
              return $ B.divWith ("",["sidebar"],[]) $ tit <> bod
        "topic" ->
           do tit <- B.para . B.strong <$> parseInlineFromString top
              bod <- parseFromString parseBlocks body'
              return $ B.divWith ("",["topic"],[]) $ tit <> bod
        "default-role" -> mempty <$ updateState (\s ->
                              s { stateRstDefaultRole =
                                  case trim top of
                                     ""   -> stateRstDefaultRole def
                                     role -> role })
        x | x == "code" || x == "code-block" ->
          codeblock (words $ fromMaybe [] $ lookup "class" fields)
                    (lookup "number-lines" fields) (trim top) body
        "aafig" -> do
          let attribs = ("", ["aafig"], map (\(k,v) -> (k, trimr v)) fields)
          return $ B.codeBlockWith attribs $ stripTrailingNewlines body
        "math" -> return $ B.para $ mconcat $ map B.displayMath
                         $ toChunks $ top ++ "\n\n" ++ body
        "figure" -> do
           (caption, legend) <- parseFromString extractCaption body'
           let src = escapeURI $ trim top
           return $ B.para (B.imageWith (imgAttr "figclass") src "fig:" caption) <> legend
        "image" -> do
           let src = escapeURI $ trim top
           let alt = B.str $ maybe "image" trim $ lookup "alt" fields
           let attr = imgAttr "class"
           return $ B.para
                  $ case lookup "target" fields of
                          Just t  -> B.link (escapeURI $ trim t) ""
                                     $ B.imageWith attr src "" alt
                          Nothing -> B.imageWith attr src "" alt
        "class" -> do
            let attrs = ("", (splitBy isSpace $ trim top), map (\(k,v) -> (k, trimr v)) fields)
            --  directive content or the first immediately following element
            children <- case body of
                "" -> block
                _ -> parseFromString parseBlocks  body'
            return $ B.divWith attrs children
        other     -> do
            pos <- getPosition
            addWarning (Just pos) $ "ignoring unknown directive: " ++ other
            return mempty

-- TODO:
--  - Only supports :format: fields with a single format for :raw: roles,
--    change Text.Pandoc.Definition.Format to fix
addNewRole :: String -> [(String, String)] -> RSTParser Blocks
addNewRole roleString fields = do
    (role, parentRole) <- parseFromString inheritedRole roleString
    customRoles <- stateRstCustomRoles <$> getState
    let getBaseRole (r, f, a) roles =
            case M.lookup r roles of
                 Just (r', f', a') -> getBaseRole (r', f', a') roles
                 Nothing -> (r, f, a)
        (baseRole, baseFmt, baseAttr) =
               getBaseRole (parentRole, Nothing, nullAttr) customRoles
        fmt = if parentRole == "raw" then lookup "format" fields else baseFmt
        annotate :: [String] -> [String]
        annotate = maybe id (:) $
            if baseRole == "code"
               then lookup "language" fields
               else Nothing
        attr = let (ident, classes, keyValues) = baseAttr
        -- nub in case role name & language class are the same
               in (ident, nub . (role :) . annotate $ classes, keyValues)

    -- warn about syntax we ignore
    flip mapM_ fields $ \(key, _) -> case key of
        "language" -> when (baseRole /= "code") $ addWarning Nothing $
            "ignoring :language: field because the parent of role :" ++
            role ++ ": is :" ++ baseRole ++ ": not :code:"
        "format" -> when (baseRole /= "raw") $ addWarning Nothing $
            "ignoring :format: field because the parent of role :" ++
            role ++ ": is :" ++ baseRole ++ ": not :raw:"
        _ -> addWarning Nothing $ "ignoring unknown field :" ++ key ++
             ": in definition of role :" ++ role ++ ": in"
    when (parentRole == "raw" && countKeys "format" > 1) $
        addWarning Nothing $
        "ignoring :format: fields after the first in the definition of role :"
        ++ role ++": in"
    when (parentRole == "code" && countKeys "language" > 1) $
        addWarning Nothing $
        "ignoring :language: fields after the first in the definition of role :"
        ++ role ++": in"

    updateState $ \s -> s {
        stateRstCustomRoles =
          M.insert role (baseRole, fmt, attr) customRoles
    }

    return $ B.singleton Null
  where
    countKeys k = length . filter (== k) . map fst $ fields
    inheritedRole =
        (,) <$> roleName <*> ((char '(' *> roleName <* char ')') <|> pure "span")


-- Can contain character codes as decimal numbers or
-- hexadecimal numbers, prefixed by 0x, x, \x, U+, u, or \u
-- or as XML-style hexadecimal character entities, e.g. &#x1a2b;
-- or text, which is used as-is.  Comments start with ..
unicodeTransform :: String -> String
unicodeTransform t =
  case t of
       ('.':'.':xs)  -> unicodeTransform $ dropWhile (/='\n') xs -- comment
       ('0':'x':xs)  -> go "0x" xs
       ('x':xs)      -> go "x" xs
       ('\\':'x':xs) -> go "\\x" xs
       ('U':'+':xs)  -> go "U+" xs
       ('u':xs)      -> go "u" xs
       ('\\':'u':xs) -> go "\\u" xs
       ('&':'#':'x':xs) -> maybe ("&#x" ++ unicodeTransform xs)
                           -- drop semicolon
                           (\(c,s) -> c : unicodeTransform (drop 1 s))
                           $ extractUnicodeChar xs
       (x:xs)        -> x : unicodeTransform xs
       []            -> []
    where go pref zs = maybe (pref ++ unicodeTransform zs)
                         (\(c,s) -> c : unicodeTransform s)
                         $ extractUnicodeChar zs

extractUnicodeChar :: String -> Maybe (Char, String)
extractUnicodeChar s = maybe Nothing (\c -> Just (c,rest)) mbc
  where (ds,rest) = span isHexDigit s
        mbc = safeRead ('\'':'\\':'x':ds ++ "'")

extractCaption :: RSTParser (Inlines, Blocks)
extractCaption = do
  capt <- trimInlines . mconcat <$> many inline
  legend <- optional blanklines >> (mconcat <$> many block)
  return (capt,legend)

-- divide string by blanklines
toChunks :: String -> [String]
toChunks = dropWhile null
           . map (trim . unlines)
           . splitBy (all (`elem` (" \t" :: String))) . lines

codeblock :: [String] -> Maybe String -> String -> String -> RSTParser Blocks
codeblock classes numberLines lang body =
  return $ B.codeBlockWith attribs $ stripTrailingNewlines body
    where attribs = ("", classes', kvs)
          classes' = "sourceCode" : lang
                    : maybe [] (\_ -> ["numberLines"]) numberLines
                    ++ classes
          kvs     = case numberLines of
                          Just "" -> []
                          Nothing -> []
                          Just n  -> [("startFrom",trim n)]

---
--- note block
---

noteBlock :: RSTParser [Char]
noteBlock = try $ do
  startPos <- getPosition
  string ".."
  spaceChar >> skipMany spaceChar
  ref <- noteMarker
  first <- (spaceChar >> skipMany spaceChar >> anyLine)
        <|> (newline >> return "")
  blanks <- option "" blanklines
  rest <- option "" indentedBlock
  endPos <- getPosition
  let raw = first ++ "\n" ++ blanks ++ rest ++ "\n"
  let newnote = (ref, raw)
  st <- getState
  let oldnotes = stateNotes st
  updateState $ \s -> s { stateNotes = newnote : oldnotes }
  -- return blanks so line count isn't affected
  return $ replicate (sourceLine endPos - sourceLine startPos) '\n'

noteMarker :: RSTParser [Char]
noteMarker = do
  char '['
  res <- many1 digit
      <|> (try $ char '#' >> liftM ('#':) simpleReferenceName')
      <|> count 1 (oneOf "#*")
  char ']'
  return res

--
-- reference key
--

quotedReferenceName :: RSTParser Inlines
quotedReferenceName = try $ do
  char '`' >> notFollowedBy (char '`') -- `` means inline code!
  label' <- trimInlines . mconcat <$> many1Till inline (char '`')
  return label'

unquotedReferenceName :: RSTParser Inlines
unquotedReferenceName = try $ do
  label' <- trimInlines . mconcat <$> many1Till inline (lookAhead $ char ':')
  return label'

-- Simple reference names are single words consisting of alphanumerics
-- plus isolated (no two adjacent) internal hyphens, underscores,
-- periods, colons and plus signs; no whitespace or other characters
-- are allowed.
simpleReferenceName' :: Parser [Char] st String
simpleReferenceName' = do
  x <- alphaNum
  xs <- many $  alphaNum
            <|> (try $ oneOf "-_:+." <* lookAhead alphaNum)
  return (x:xs)

simpleReferenceName :: Parser [Char] st Inlines
simpleReferenceName = do
  raw <- simpleReferenceName'
  return $ B.str raw

referenceName :: RSTParser Inlines
referenceName = quotedReferenceName <|>
                (try $ simpleReferenceName <* lookAhead (char ':')) <|>
                unquotedReferenceName

referenceKey :: RSTParser [Char]
referenceKey = do
  startPos <- getPosition
  choice [substKey, anonymousKey, regularKey]
  optional blanklines
  endPos <- getPosition
  -- return enough blanks to replace key
  return $ replicate (sourceLine endPos - sourceLine startPos) '\n'

targetURI :: Parser [Char] st [Char]
targetURI = do
  skipSpaces
  optional newline
  contents <- many1 (try (many spaceChar >> newline >>
                          many1 spaceChar >> noneOf " \t\n") <|> noneOf "\n")
  blanklines
  return $ escapeURI $ trim $ contents

substKey :: RSTParser ()
substKey = try $ do
  string ".."
  skipMany1 spaceChar
  (alt,ref) <- withRaw $ trimInlines . mconcat
                      <$> enclosed (char '|') (char '|') inline
  res <- B.toList <$> directive'
  il <- case res of
             -- use alt unless :alt: attribute on image:
             [Para [Image attr [Str "image"] (src,tit)]] ->
                return $ B.imageWith attr src tit alt
             [Para [Link _ [Image attr [Str "image"] (src,tit)] (src',tit')]] ->
                return $ B.link src' tit' (B.imageWith attr src tit alt)
             [Para ils] -> return $ B.fromList ils
             _          -> mzero
  let key = toKey $ stripFirstAndLast ref
  updateState $ \s -> s{ stateSubstitutions = M.insert key il $ stateSubstitutions s }

anonymousKey :: RSTParser ()
anonymousKey = try $ do
  oneOfStrings [".. __:", "__"]
  src <- targetURI
  pos <- getPosition
  let key = toKey $ "_" ++ printf "%09d" (sourceLine pos)
  --TODO: parse width, height, class and name attributes
  updateState $ \s -> s { stateKeys = M.insert key ((src,""), nullAttr) $ stateKeys s }

stripTicks :: String -> String
stripTicks = reverse . stripTick . reverse . stripTick
  where stripTick ('`':xs) = xs
        stripTick xs = xs

regularKey :: RSTParser ()
regularKey = try $ do
  string ".. _"
  (_,ref) <- withRaw referenceName
  char ':'
  src <- targetURI
  let key = toKey $ stripTicks ref
  --TODO: parse width, height, class and name attributes
  updateState $ \s -> s { stateKeys = M.insert key ((src,""), nullAttr) $ stateKeys s }

--
-- tables
--

-- General tables TODO:
--  - figure out if leading spaces are acceptable and if so, add
--    support for them
--
-- Simple tables TODO:
--  - column spans
--  - multiline support
--  - ensure that rightmost column span does not need to reach end
--  - require at least 2 columns
--
-- Grid tables TODO:
--  - column spans

dashedLine :: Char -> Parser [Char] st (Int, Int)
dashedLine ch = do
  dashes <- many1 (char ch)
  sp     <- many (char ' ')
  return (length dashes, length $ dashes ++ sp)

simpleDashedLines :: Char -> Parser [Char] st [(Int,Int)]
simpleDashedLines ch = try $ many1 (dashedLine ch)

-- Parse a table row separator
simpleTableSep :: Char -> RSTParser Char
simpleTableSep ch = try $ simpleDashedLines ch >> newline

-- Parse a table footer
simpleTableFooter :: RSTParser [Char]
simpleTableFooter = try $ simpleTableSep '=' >> blanklines

-- Parse a raw line and split it into chunks by indices.
simpleTableRawLine :: [Int] -> RSTParser [String]
simpleTableRawLine indices = do
  line <- many1Till anyChar newline
  return (simpleTableSplitLine indices line)

-- Parse a table row and return a list of blocks (columns).
simpleTableRow :: [Int] -> RSTParser [[Block]]
simpleTableRow indices = do
  notFollowedBy' simpleTableFooter
  firstLine <- simpleTableRawLine indices
  colLines  <- return [] -- TODO
  let cols = map unlines . transpose $ firstLine : colLines
  mapM (parseFromString (B.toList . mconcat <$> many plain)) cols

simpleTableSplitLine :: [Int] -> String -> [String]
simpleTableSplitLine indices line =
  map trim
  $ tail $ splitByIndices (init indices) line

simpleTableHeader :: Bool  -- ^ Headerless table
                  -> RSTParser ([[Block]], [Alignment], [Int])
simpleTableHeader headless = try $ do
  optional blanklines
  rawContent  <- if headless
                    then return ""
                    else simpleTableSep '=' >> anyLine
  dashes      <- simpleDashedLines '=' <|> simpleDashedLines '-'
  newline
  let lines'   = map snd dashes
  let indices  = scanl (+) 0 lines'
  let aligns   = replicate (length lines') AlignDefault
  let rawHeads = if headless
                    then replicate (length dashes) ""
                    else simpleTableSplitLine indices rawContent
  heads <- mapM (parseFromString (B.toList . mconcat <$> many plain)) $
             map trim rawHeads
  return (heads, aligns, indices)

-- Parse a simple table.
simpleTable :: Bool  -- ^ Headerless table
            -> RSTParser Blocks
simpleTable headless = do
  Table c a _w h l <- tableWith (simpleTableHeader headless) simpleTableRow sep simpleTableFooter
  -- Simple tables get 0s for relative column widths (i.e., use default)
  return $ B.singleton $ Table c a (replicate (length a) 0) h l
 where
  sep = return () -- optional (simpleTableSep '-')

gridTable :: Bool -- ^ Headerless table
          -> RSTParser Blocks
gridTable headerless = B.singleton
  <$> gridTableWith (B.toList <$> parseBlocks) headerless

table :: RSTParser Blocks
table = gridTable False <|> simpleTable False <|>
        gridTable True  <|> simpleTable True <?> "table"

--
-- inline
--

inline :: RSTParser Inlines
inline = choice [ whitespace
                , link
                , str
                , endline
                , strong
                , emph
                , code
                , subst
                , interpretedRole
                , note
                , smart
                , hyphens
                , escapedChar
                , symbol ] <?> "inline"

parseInlineFromString :: String -> RSTParser Inlines
parseInlineFromString = parseFromString (trimInlines . mconcat <$> many inline)

hyphens :: RSTParser Inlines
hyphens = do
  result <- many1 (char '-')
  optional endline
  -- don't want to treat endline after hyphen or dash as a space
  return $ B.str result

escapedChar :: Parser [Char] st Inlines
escapedChar = do c <- escaped anyChar
                 return $ if c == ' '  -- '\ ' is null in RST
                             then mempty
                             else B.str [c]

symbol :: RSTParser Inlines
symbol = do
  result <- oneOf specialChars
  return $ B.str [result]

-- parses inline code, between codeStart and codeEnd
code :: RSTParser Inlines
code = try $ do
  string "``"
  result <- manyTill anyChar (try (string "``"))
  return $ B.code
         $ trim $ unwords $ lines result

-- succeeds only if we're not right after a str (ie. in middle of word)
atStart :: RSTParser a -> RSTParser a
atStart p = do
  pos <- getPosition
  st <- getState
  -- single quote start can't be right after str
  guard $ stateLastStrPos st /= Just pos
  p

emph :: RSTParser Inlines
emph = B.emph . trimInlines . mconcat <$>
         enclosed (atStart $ char '*') (char '*') inline

strong :: RSTParser Inlines
strong = B.strong . trimInlines . mconcat <$>
          enclosed (atStart $ string "**") (try $ string "**") inline

-- Note, this doesn't precisely implement the complex rule in
-- http://docutils.sourceforge.net/docs/ref/rst/restructuredtext.html#inline-markup-recognition-rules
-- but it should be good enough for most purposes
--
-- TODO:
--  - Classes are silently discarded in addNewRole
--  - Lacks sensible implementation for title-reference (which is the default)
--  - Allows direct use of the :raw: role, rST only allows inherited use.
interpretedRole :: RSTParser Inlines
interpretedRole = try $ do
  (role, contents) <- roleBefore <|> roleAfter
  renderRole contents Nothing role nullAttr

renderRole :: String -> Maybe String -> String -> Attr -> RSTParser Inlines
renderRole contents fmt role attr = case role of
    "sup"  -> return $ B.superscript $ B.str contents
    "superscript" -> return $ B.superscript $ B.str contents
    "sub"  -> return $ B.subscript $ B.str contents
    "subscript"  -> return $ B.subscript $ B.str contents
    "emphasis" -> return $ B.emph $ B.str contents
    "strong" -> return $ B.strong $ B.str contents
    "rfc-reference" -> return $ rfcLink contents
    "RFC" -> return $ rfcLink contents
    "pep-reference" -> return $ pepLink contents
    "PEP" -> return $ pepLink contents
    "literal" -> return $ B.codeWith attr contents
    "math" -> return $ B.math contents
    "title-reference" -> titleRef contents
    "title" -> titleRef contents
    "t" -> titleRef contents
    "code" -> return $ B.codeWith (addClass "sourceCode" attr) contents
    "span" -> return $ B.spanWith attr $ B.str contents
    "raw" -> return $ B.rawInline (fromMaybe "" fmt) contents
    custom -> do
        customRoles <- stateRstCustomRoles <$> getState
        case M.lookup custom customRoles of
            Just (newRole, newFmt, newAttr) ->
                renderRole contents newFmt newRole newAttr
            Nothing -> do
                pos <- getPosition
                addWarning (Just pos) $ "ignoring unknown role :" ++ custom ++ ": in"
                return $ B.str contents -- Undefined role
 where
   titleRef ref = return $ B.str ref -- FIXME: Not a sensible behaviour
   rfcLink rfcNo = B.link rfcUrl ("RFC " ++ rfcNo) $ B.str ("RFC " ++ rfcNo)
     where rfcUrl = "http://www.faqs.org/rfcs/rfc" ++ rfcNo ++ ".html"
   pepLink pepNo = B.link pepUrl ("PEP " ++ pepNo) $ B.str ("PEP " ++ pepNo)
     where padNo = replicate (4 - length pepNo) '0' ++ pepNo
           pepUrl = "http://www.python.org/dev/peps/pep-" ++ padNo ++ "/"

addClass :: String -> Attr -> Attr
addClass c (ident, classes, keyValues) = (ident, union classes [c], keyValues)

roleName :: RSTParser String
roleName = many1 (letter <|> char '-')

roleMarker :: RSTParser String
roleMarker = char ':' *> roleName <* char ':'

roleBefore :: RSTParser (String,String)
roleBefore = try $ do
  role <- roleMarker
  contents <- unmarkedInterpretedText
  return (role,contents)

roleAfter :: RSTParser (String,String)
roleAfter = try $ do
  contents <- unmarkedInterpretedText
  role <- roleMarker <|> (stateRstDefaultRole <$> getState)
  return (role,contents)

unmarkedInterpretedText :: RSTParser [Char]
unmarkedInterpretedText = enclosed (atStart $ char '`') (char '`') anyChar

whitespace :: RSTParser Inlines
whitespace = B.space <$ skipMany1 spaceChar <?> "whitespace"

str :: RSTParser Inlines
str = do
  let strChar = noneOf ("\t\n " ++ specialChars)
  result <- many1 strChar
  updateLastStrPos
  return $ B.str result

-- an endline character that can be treated as a space, not a structural break
endline :: RSTParser Inlines
endline = try $ do
  newline
  notFollowedBy blankline
  -- parse potential list-starts at beginning of line differently in a list:
  st <- getState
  if (stateParserContext st) == ListItemState
     then notFollowedBy (anyOrderedListMarker >> spaceChar) >>
          notFollowedBy' bulletListStart
     else return ()
  return B.softbreak

--
-- links
--

link :: RSTParser Inlines
link = choice [explicitLink, referenceLink, autoLink]  <?> "link"

explicitLink :: RSTParser Inlines
explicitLink = try $ do
  char '`'
  notFollowedBy (char '`') -- `` marks start of inline code
  label' <- trimInlines . mconcat <$>
             manyTill (notFollowedBy (char '`') >> inline) (char '<')
  src <- manyTill (noneOf ">\n") (char '>')
  skipSpaces
  string "`_"
  optional $ char '_' -- anonymous form
  let label'' = if label' == mempty
                   then B.str src
                   else label'
  return $ B.link (escapeURI $ trim src) "" label''

referenceLink :: RSTParser Inlines
referenceLink = try $ do
  (label',ref) <- withRaw (quotedReferenceName <|> simpleReferenceName) <*
                   char '_'
  state <- getState
  let keyTable = stateKeys state
  let isAnonKey (Key ('_':_)) = True
      isAnonKey _             = False
  key <- option (toKey $ stripTicks ref) $
                do char '_'
                   let anonKeys = sort $ filter isAnonKey $ M.keys keyTable
                   if null anonKeys
                      then mzero
                      else return (head anonKeys)
  ((src,tit), attr) <- case M.lookup key keyTable of
                         Nothing  -> fail "no corresponding key"
                         Just val -> return val
  -- if anonymous link, remove key so it won't be used again
  when (isAnonKey key) $ updateState $ \s -> s{ stateKeys = M.delete key keyTable }
  return $ B.linkWith attr src tit label'

autoURI :: RSTParser Inlines
autoURI = do
  (orig, src) <- uri
  return $ B.link src "" $ B.str orig

autoEmail :: RSTParser Inlines
autoEmail = do
  (orig, src) <- emailAddress
  return $ B.link src "" $ B.str orig

autoLink :: RSTParser Inlines
autoLink = autoURI <|> autoEmail

subst :: RSTParser Inlines
subst = try $ do
  (_,ref) <- withRaw $ enclosed (char '|') (char '|') inline
  state <- getState
  let substTable = stateSubstitutions state
  case M.lookup (toKey $ stripFirstAndLast ref) substTable of
       Nothing     -> fail "no corresponding key"
       Just target -> return target

note :: RSTParser Inlines
note = try $ do
  ref <- noteMarker
  char '_'
  state <- getState
  let notes = stateNotes state
  case lookup ref notes of
    Nothing   -> fail "note not found"
    Just raw  -> do
      -- We temporarily empty the note list while parsing the note,
      -- so that we don't get infinite loops with notes inside notes...
      -- Note references inside other notes are allowed in reST, but
      -- not yet in this implementation.
      updateState $ \st -> st{ stateNotes = [] }
      contents <- parseFromString parseBlocks raw
      let newnotes = if (ref == "*" || ref == "#") -- auto-numbered
                        -- delete the note so the next auto-numbered note
                        -- doesn't get the same contents:
                        then deleteFirstsBy (==) notes [(ref,raw)]
                        else notes
      updateState $ \st -> st{ stateNotes = newnotes }
      return $ B.note contents

smart :: RSTParser Inlines
smart = do
  getOption readerSmart >>= guard
  doubleQuoted <|> singleQuoted <|>
    choice [apostrophe, dash, ellipses]

singleQuoted :: RSTParser Inlines
singleQuoted = try $ do
  singleQuoteStart
  withQuoteContext InSingleQuote $
    B.singleQuoted . trimInlines . mconcat <$>
      many1Till inline singleQuoteEnd

doubleQuoted :: RSTParser Inlines
doubleQuoted = try $ do
  doubleQuoteStart
  withQuoteContext InDoubleQuote $
    B.doubleQuoted . trimInlines . mconcat <$>
      many1Till inline doubleQuoteEnd