aboutsummaryrefslogtreecommitdiff
path: root/src/Text/Pandoc/Readers/Textile.hs
blob: 5aae11751395e4609f244173fe83fd1df66a30b3 (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
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ViewPatterns      #-}
{- |
   Module      : Text.Pandoc.Readers.Textile
   Copyright   : Copyright (C) 2010-2012 Paul Rivier
                               2010-2020 John MacFarlane
   License     : GNU GPL, version 2 or above

   Maintainer  : Paul Rivier <paul*rivier#demotera*com>
   Stability   : alpha
   Portability : portable

Conversion from Textile to 'Pandoc' document, based on the spec
available at http://redcloth.org/textile.

Implemented and parsed:
 - Paragraphs
 - Code blocks
 - Lists
 - blockquote
 - Inlines : strong, emph, cite, code, deleted, superscript,
   subscript, links
 - footnotes
 - HTML-specific and CSS-specific attributes on headers

Left to be implemented:
 - dimension sign
 - all caps
 - continued blocks (ex bq..)

TODO : refactor common patterns across readers :
 - more ...

-}


module Text.Pandoc.Readers.Textile ( readTextile) where
import Control.Monad (guard, liftM)
import Control.Monad.Except (throwError)
import Data.Char (digitToInt, isUpper)
import Data.List (intersperse, transpose)
import Data.Text (Text)
import qualified Data.Text as T
import Text.HTML.TagSoup (Tag (..), fromAttrib)
import Text.HTML.TagSoup.Match
import Text.Pandoc.Builder (Blocks, Inlines, trimInlines)
import qualified Text.Pandoc.Builder as B
import Text.Pandoc.Class.PandocMonad (PandocMonad (..))
import Text.Pandoc.CSS
import Text.Pandoc.Definition
import Text.Pandoc.Options
import Text.Pandoc.Parsing
import Text.Pandoc.Readers.HTML (htmlTag, isBlockTag, isInlineTag)
import Text.Pandoc.Readers.LaTeX (rawLaTeXBlock, rawLaTeXInline)
import Text.Pandoc.Shared (crFilter, trim, underlineSpan, tshow)

-- | Parse a Textile text and return a Pandoc document.
readTextile :: PandocMonad m
            => ReaderOptions -- ^ Reader options
            -> Text          -- ^ String to parse (assuming @'\n'@ line endings)
            -> m Pandoc
readTextile opts s = do
  parsed <- readWithM parseTextile def{ stateOptions = opts }
                (crFilter s <> "\n\n")
  case parsed of
     Right result -> return result
     Left e       -> throwError e


-- | Generate a Pandoc ADT from a textile document
parseTextile :: PandocMonad m => ParserT Text ParserState m Pandoc
parseTextile = do
  many blankline
  startPos <- getPosition
  -- go through once just to get list of reference keys and notes
  -- docMinusKeys is the raw document with blanks where the keys/notes were...
  let firstPassParser = noteBlock <|> lineClump
  manyTill firstPassParser eof >>= setInput . T.concat
  setPosition startPos
  st' <- getState
  let reversedNotes = stateNotes st'
  updateState $ \s -> s { stateNotes = reverse reversedNotes }
  -- now parse it for real...
  Pandoc nullMeta . B.toList <$> parseBlocks -- FIXME

noteMarker :: PandocMonad m => ParserT Text ParserState m Text
noteMarker = skipMany spaceChar >> string "fn" >> T.pack <$> manyTill digit (char '.')

noteBlock :: PandocMonad m => ParserT Text ParserState m Text
noteBlock = try $ do
  startPos <- getPosition
  ref <- noteMarker
  optional blankline
  contents <- T.unlines <$> many1Till anyLine (blanklines <|> noteBlock)
  endPos <- getPosition
  let newnote = (ref, contents <> "\n")
  st <- getState
  let oldnotes = stateNotes st
  updateState $ \s -> s { stateNotes = newnote : oldnotes }
  -- return blanks so line count isn't affected
  return $ T.replicate (sourceLine endPos - sourceLine startPos) "\n"

-- | Parse document blocks
parseBlocks :: PandocMonad m => ParserT Text ParserState m Blocks
parseBlocks = mconcat <$> manyTill block eof

-- | Block parsers list tried in definition order
blockParsers :: PandocMonad m => [ParserT Text ParserState m Blocks]
blockParsers = [ codeBlock
               , header
               , blockQuote
               , hrule
               , commentBlock
               , anyList
               , rawHtmlBlock
               , rawLaTeXBlock'
               , table
               , maybeExplicitBlock "p" para
               , mempty <$ blanklines
               ]

-- | Any block in the order of definition of blockParsers
block :: PandocMonad m => ParserT Text ParserState m Blocks
block = do
  res <- choice blockParsers <?> "block"
  trace (T.take 60 $ tshow $ B.toList res)
  return res

commentBlock :: PandocMonad m => ParserT Text ParserState m Blocks
commentBlock = try $ do
  string "###."
  manyTill anyLine blanklines
  return mempty

codeBlock :: PandocMonad m => ParserT Text ParserState m Blocks
codeBlock = codeBlockBc <|> codeBlockPre

codeBlockBc :: PandocMonad m => ParserT Text ParserState m Blocks
codeBlockBc = try $ do
  string "bc."
  extended <- option False (True <$ char '.')
  char ' '
  let starts = ["p", "table", "bq", "bc", "h1", "h2", "h3",
                "h4", "h5", "h6", "pre", "###", "notextile"]
  let ender = choice $ map explicitBlockStart starts
  contents <- if extended
                 then do
                   f <- anyLine
                   rest <- many (notFollowedBy ender *> anyLine)
                   return (f:rest)
                 else manyTill anyLine blanklines
  return $ B.codeBlock (trimTrailingNewlines (T.unlines contents))

trimTrailingNewlines :: Text -> Text
trimTrailingNewlines = T.dropWhileEnd (=='\n')

-- | Code Blocks in Textile are between <pre> and </pre>
codeBlockPre :: PandocMonad m => ParserT Text ParserState m Blocks
codeBlockPre = try $ do
  (t@(TagOpen _ attrs),_) <- htmlTag (tagOpen (=="pre") (const True))
  result' <- T.pack <$> manyTill anyChar (htmlTag (tagClose (=="pre")))
  -- drop leading newline if any
  let result'' = case T.uncons result' of
                   Just ('\n', xs) -> xs
                   _               -> result'
  -- drop trailing newline if any
  let result''' = case T.unsnoc result'' of
                    Just (xs, '\n') -> xs
                    _               -> result''
  let classes = T.words $ fromAttrib "class" t
  let ident = fromAttrib "id" t
  let kvs = [(k,v) | (k,v) <- attrs, k /= "id" && k /= "class"]
  return $ B.codeBlockWith (ident,classes,kvs) result'''

-- | Header of the form "hN. content" with N in 1..6
header :: PandocMonad m => ParserT Text ParserState m Blocks
header = try $ do
  char 'h'
  level <- digitToInt <$> oneOf "123456"
  attr <- attributes
  char '.'
  lookAhead whitespace
  name <- trimInlines . mconcat <$> many inline
  attr' <- registerHeader attr name
  return $ B.headerWith attr' level name

-- | Blockquote of the form "bq. content"
blockQuote :: PandocMonad m => ParserT Text ParserState m Blocks
blockQuote = try $ do
  string "bq" >> attributes >> char '.' >> whitespace
  B.blockQuote <$> para

-- Horizontal rule

hrule :: PandocMonad m => ParserT Text st m Blocks
hrule = try $ do
  skipSpaces
  start <- oneOf "-*"
  count 2 (skipSpaces >> char start)
  skipMany (spaceChar <|> char start)
  newline
  optional blanklines
  return B.horizontalRule

-- Lists handling

-- | Can be a bullet list or an ordered list. This implementation is
-- strict in the nesting, sublist must start at exactly "parent depth
-- plus one"
anyList :: PandocMonad m => ParserT Text ParserState m Blocks
anyList = try $ anyListAtDepth 1 <* blanklines

-- | This allow one type of list to be nested into an other type,
-- provided correct nesting
anyListAtDepth :: PandocMonad m => Int -> ParserT Text ParserState m Blocks
anyListAtDepth depth = choice [ bulletListAtDepth depth,
                                orderedListAtDepth depth,
                                definitionList ]

-- | Bullet List of given depth, depth being the number of leading '*'
bulletListAtDepth :: PandocMonad m => Int -> ParserT Text ParserState m Blocks
bulletListAtDepth depth = try $ B.bulletList  <$> many1 (bulletListItemAtDepth depth)

-- | Bullet List Item of given depth, depth being the number of
-- leading '*'
bulletListItemAtDepth :: PandocMonad m => Int -> ParserT Text ParserState m Blocks
bulletListItemAtDepth = genericListItemAtDepth '*'

-- | Ordered List of given depth, depth being the number of
-- leading '#'
orderedListAtDepth :: PandocMonad m => Int -> ParserT Text ParserState m Blocks
orderedListAtDepth depth = try $ do
  items <- many1 (orderedListItemAtDepth depth)
  return $ B.orderedList items

-- | Ordered List Item of given depth, depth being the number of
-- leading '#'
orderedListItemAtDepth :: PandocMonad m => Int -> ParserT Text ParserState m Blocks
orderedListItemAtDepth = genericListItemAtDepth '#'

-- | Common implementation of list items
genericListItemAtDepth :: PandocMonad m => Char -> Int -> ParserT Text ParserState m Blocks
genericListItemAtDepth c depth = try $ do
  count depth (char c) >> attributes >> whitespace
  contents <- mconcat <$> many ((B.plain . mconcat <$> many1 inline) <|>
                                try (newline >> codeBlockPre))
  newline
  sublist <- option mempty (anyListAtDepth (depth + 1))
  return $ contents <> sublist

-- | A definition list is a set of consecutive definition items
definitionList :: PandocMonad m => ParserT Text ParserState m Blocks
definitionList = try $ B.definitionList <$> many1 definitionListItem

-- | List start character.
listStart :: PandocMonad m => ParserT Text ParserState m ()
listStart = genericListStart '*'
        <|> () <$ genericListStart '#'
        <|> () <$ definitionListStart

genericListStart :: PandocMonad m => Char -> ParserT Text st m ()
genericListStart c = () <$ try (many1 (char c) >> whitespace)

basicDLStart :: PandocMonad m => ParserT Text ParserState m ()
basicDLStart = do
  char '-'
  whitespace
  notFollowedBy newline

definitionListStart :: PandocMonad m => ParserT Text ParserState m Inlines
definitionListStart = try $ do
  basicDLStart
  trimInlines . mconcat <$>
    many1Till inline
     (  try (newline *> lookAhead basicDLStart)
    <|> try (lookAhead (() <$ string ":="))
     )

-- | A definition list item in textile begins with '- ', followed by
-- the term defined, then spaces and ":=". The definition follows, on
-- the same single line, or spaned on multiple line, after a line
-- break.
definitionListItem :: PandocMonad m => ParserT Text ParserState m (Inlines, [Blocks])
definitionListItem = try $ do
  term <- (mconcat . intersperse B.linebreak) <$> many1 definitionListStart
  def' <- string ":=" *> optional whitespace *> (multilineDef <|> inlineDef)
  return (term, def')
  where inlineDef :: PandocMonad m => ParserT Text ParserState m [Blocks]
        inlineDef = liftM (\d -> [B.plain d])
                    $ optional whitespace >> (trimInlines . mconcat <$> many inline) <* newline
        multilineDef :: PandocMonad m => ParserT Text ParserState m [Blocks]
        multilineDef = try $ do
          optional whitespace >> newline
          s <- T.pack <$> many1Till anyChar (try (string "=:" >> newline))
          -- this <> "\n\n" does not look very good
          ds <- parseFromString' parseBlocks (s <> "\n\n")
          return [ds]

-- raw content

-- | A raw Html Block, optionally followed by blanklines
rawHtmlBlock :: PandocMonad m => ParserT Text ParserState m Blocks
rawHtmlBlock = try $ do
  skipMany spaceChar
  (_,b) <- htmlTag isBlockTag
  optional blanklines
  return $ B.rawBlock "html" b

-- | Raw block of LaTeX content
rawLaTeXBlock' :: PandocMonad m => ParserT Text ParserState m Blocks
rawLaTeXBlock' = do
  guardEnabled Ext_raw_tex
  B.rawBlock "latex" <$> (rawLaTeXBlock <* spaces)


-- | In textile, paragraphs are separated by blank lines.
para :: PandocMonad m => ParserT Text ParserState m Blocks
para = B.para . trimInlines . mconcat <$> many1 inline

-- Tables

toAlignment :: Char -> Alignment
toAlignment '<' = AlignLeft
toAlignment '>' = AlignRight
toAlignment '=' = AlignCenter
toAlignment _   = AlignDefault

cellAttributes :: PandocMonad m => ParserT Text ParserState m (Bool, Alignment)
cellAttributes = try $ do
  isHeader <- option False (True <$ char '_')
  -- we just ignore colspan and rowspan markers:
  optional $ try $ oneOf "/\\" >> many1 digit
  -- we pay attention to alignments:
  alignment <- option AlignDefault $ toAlignment <$> oneOf "<>="
  -- ignore other attributes for now:
  _ <- attributes
  char '.'
  return (isHeader, alignment)

-- | A table cell spans until a pipe |
tableCell :: PandocMonad m => ParserT Text ParserState m ((Bool, Alignment), Blocks)
tableCell = try $ do
  char '|'
  (isHeader, alignment) <- option (False, AlignDefault) cellAttributes
  notFollowedBy blankline
  raw <- trim . T.pack <$>
         many (noneOf "|\n" <|> try (char '\n' <* notFollowedBy blankline))
  content <- mconcat <$> parseFromString' (many inline) raw
  return ((isHeader, alignment), B.plain content)

-- | A table row is made of many table cells
tableRow :: PandocMonad m => ParserT Text ParserState m [((Bool, Alignment), Blocks)]
tableRow = try $ do
  -- skip optional row attributes
  optional $ try $ do
    _ <- attributes
    char '.'
    many1 spaceChar
  many1 tableCell <* char '|' <* blankline

-- | A table with an optional header.
table :: PandocMonad m => ParserT Text ParserState m Blocks
table = try $ do
  -- ignore table attributes
  caption <- option mempty $ try $ do
    string "table"
    _ <- attributes
    char '.'
    rawcapt <- trim <$> anyLine
    parseFromString' (mconcat <$> many inline) rawcapt
  rawrows <- many1 $ skipMany ignorableRow >> tableRow
  skipMany ignorableRow
  blanklines
  let (headers, rows) = case rawrows of
                             (toprow:rest) | any (fst . fst) toprow ->
                                (toprow, rest)
                             _ -> (mempty, rawrows)
  let nbOfCols = maximum $ map length (headers:rows)
  let aligns = map minimum $ transpose $ map (map (snd . fst)) (headers:rows)
  return $ B.table caption
    (zip aligns (replicate nbOfCols 0.0))
    (map snd headers)
    (map (map snd) rows)

-- | Ignore markers for cols, thead, tfoot.
ignorableRow :: PandocMonad m => ParserT Text ParserState m ()
ignorableRow = try $ do
  char '|'
  oneOf ":^-~"
  _ <- attributes
  char '.'
  _ <- anyLine
  return ()

explicitBlockStart :: PandocMonad m => Text -> ParserT Text ParserState m ()
explicitBlockStart name = try $ do
  string (T.unpack name)
  attributes
  char '.'
  optional whitespace
  optional endline

-- | Blocks like 'p' and 'table' do not need explicit block tag.
-- However, they can be used to set HTML/CSS attributes when needed.
maybeExplicitBlock :: PandocMonad m
                   => Text  -- ^ block tag name
                   -> ParserT Text ParserState m Blocks -- ^ implicit block
                   -> ParserT Text ParserState m Blocks
maybeExplicitBlock name blk = try $ do
  optional $ explicitBlockStart name
  blk



----------
-- Inlines
----------


-- | Any inline element
inline :: PandocMonad m => ParserT Text ParserState m Inlines
inline = choice inlineParsers <?> "inline"

-- | Inline parsers tried in order
inlineParsers :: PandocMonad m => [ParserT Text ParserState m Inlines]
inlineParsers = [ str
                , whitespace
                , endline
                , code
                , escapedInline
                , inlineMarkup
                , groupedInlineMarkup
                , rawHtmlInline
                , rawLaTeXInline'
                , note
                , link
                , image
                , mark
                , (B.str . T.singleton) <$> characterReference
                , smartPunctuation inline
                , symbol
                ]

-- | Inline markups
inlineMarkup :: PandocMonad m => ParserT Text ParserState m Inlines
inlineMarkup = choice [ simpleInline (string "??") (B.cite [])
                      , simpleInline (string "**") B.strong
                      , simpleInline (string "__") B.emph
                      , simpleInline (char '*') B.strong
                      , simpleInline (char '_') B.emph
                      , simpleInline (char '+') underlineSpan
                      , simpleInline (char '-' <* notFollowedBy (char '-')) B.strikeout
                      , simpleInline (char '^') B.superscript
                      , simpleInline (char '~') B.subscript
                      , simpleInline (char '%') id
                      ]

-- | Trademark, registered, copyright
mark :: PandocMonad m => ParserT Text st m Inlines
mark = try $ char '(' >> (try tm <|> try reg <|> copy)

reg :: PandocMonad m => ParserT Text st m Inlines
reg = do
  oneOf "Rr"
  char ')'
  return $ B.str "\174"

tm :: PandocMonad m => ParserT Text st m Inlines
tm = do
  oneOf "Tt"
  oneOf "Mm"
  char ')'
  return $ B.str "\8482"

copy :: PandocMonad m => ParserT Text st m Inlines
copy = do
  oneOf "Cc"
  char ')'
  return $ B.str "\169"

note :: PandocMonad m => ParserT Text ParserState m Inlines
note = try $ do
  ref <- char '[' *> many1 digit <* char ']'
  notes <- stateNotes <$> getState
  case lookup (T.pack ref) notes of
    Nothing  -> Prelude.fail "note not found"
    Just raw -> B.note <$> parseFromString' parseBlocks raw

-- | Special chars
markupChars :: [Char]
markupChars = "\\*#_@~-+^|%=[]&"

-- | Break strings on following chars. Space tab and newline break for
--  inlines breaking. Open paren breaks for mark. Quote, dash and dot
--  break for smart punctuation. Punctuation breaks for regular
--  punctuation. Double quote breaks for named links. > and < break
--  for inline html.
stringBreakers :: [Char]
stringBreakers = " \t\n\r.,\"'?!;:<>«»„“”‚‘’()[]"

wordBoundaries :: [Char]
wordBoundaries = markupChars <> stringBreakers

-- | Parse a hyphened sequence of words
hyphenedWords :: PandocMonad m => ParserT Text ParserState m Text
hyphenedWords = do
  x <- wordChunk
  xs <-  many (try $ char '-' >> wordChunk)
  return $ T.intercalate "-" (x:xs)

wordChunk :: PandocMonad m => ParserT Text ParserState m Text
wordChunk = try $ do
  hd <- noneOf wordBoundaries
  tl <- many ( noneOf wordBoundaries <|>
               try (notFollowedBy' note *> oneOf markupChars
                     <* lookAhead (noneOf wordBoundaries) ) )
  return $ T.pack $ hd:tl

-- | Any string
str :: PandocMonad m => ParserT Text ParserState m Inlines
str = do
  baseStr <- hyphenedWords
  -- RedCloth compliance : if parsed word is uppercase and immediately
  -- followed by parens, parens content is unconditionally word acronym
  fullStr <- option baseStr $ try $ do
    guard $ T.all isUpper baseStr
    acro <- T.pack <$> enclosed (char '(') (char ')') anyChar'
    return $ T.concat [baseStr, " (", acro, ")"]
  updateLastStrPos
  return $ B.str fullStr

-- | Some number of space chars
whitespace :: PandocMonad m => ParserT Text st m Inlines
whitespace = many1 spaceChar >> return B.space <?> "whitespace"

-- | In Textile, an isolated endline character is a line break
endline :: PandocMonad m => ParserT Text ParserState m Inlines
endline = try $ do
  newline
  notFollowedBy blankline
  notFollowedBy listStart
  notFollowedBy rawHtmlBlock
  return B.linebreak

rawHtmlInline :: PandocMonad m => ParserT Text ParserState m Inlines
rawHtmlInline = B.rawInline "html" . snd <$> htmlTag isInlineTag

-- | Raw LaTeX Inline
rawLaTeXInline' :: PandocMonad m => ParserT Text ParserState m Inlines
rawLaTeXInline' = try $ do
  guardEnabled Ext_raw_tex
  B.rawInline "latex" <$> rawLaTeXInline

-- | Textile standard link syntax is "label":target. But we
-- can also have ["label":target].
link :: PandocMonad m => ParserT Text ParserState m Inlines
link = try $ do
  bracketed <- (True <$ char '[') <|> return False
  char '"' *> notFollowedBy (oneOf " \t\n\r")
  attr <- attributes
  name <- trimInlines . mconcat <$>
          withQuoteContext InDoubleQuote (many1Till inline (char '"'))
  char ':'
  let stop = if bracketed
                then char ']'
                else lookAhead $ space <|> eof' <|>
                       try (oneOf "!.,;:" *>
                              (space <|> newline <|> eof'))
  url <- T.pack <$> many1Till nonspaceChar stop
  let name' = if B.toList name == [Str "$"] then B.str url else name
  return $ if attr == nullAttr
              then B.link url "" name'
              else B.spanWith attr $ B.link url "" name'

-- | image embedding
image :: PandocMonad m => ParserT Text ParserState m Inlines
image = try $ do
  char '!' >> notFollowedBy space
  (ident, cls, kvs) <- attributes
  let attr = case lookup "style" kvs of
               Just stls -> (ident, cls, pickStylesToKVs ["width", "height"] stls)
               Nothing   -> (ident, cls, kvs)
  src <- T.pack <$> many1 (noneOf " \t\n\r!(")
  alt <- fmap T.pack $ option "" $ try $ char '(' *> manyTill anyChar (char ')')
  char '!'
  return $ B.imageWith attr src alt (B.str alt)

escapedInline :: PandocMonad m => ParserT Text ParserState m Inlines
escapedInline = escapedEqs <|> escapedTag

escapedEqs :: PandocMonad m => ParserT Text ParserState m Inlines
escapedEqs = B.str . T.pack <$>
  try (string "==" *> manyTill anyChar' (try $ string "=="))

-- | literal text escaped btw <notextile> tags
escapedTag :: PandocMonad m => ParserT Text ParserState m Inlines
escapedTag = B.str . T.pack <$>
  try (string "<notextile>" *>
         manyTill anyChar' (try $ string "</notextile>"))

-- | Any special symbol defined in wordBoundaries
symbol :: PandocMonad m => ParserT Text ParserState m Inlines
symbol = B.str . T.singleton <$> (notFollowedBy newline *>
                                  notFollowedBy rawHtmlBlock *>
                                  oneOf wordBoundaries)

-- | Inline code
code :: PandocMonad m => ParserT Text ParserState m Inlines
code = code1 <|> code2

-- any character except a newline before a blank line
anyChar' :: PandocMonad m => ParserT Text ParserState m Char
anyChar' =
  satisfy (/='\n') <|>
  try (char '\n' <* notFollowedBy blankline)

code1 :: PandocMonad m => ParserT Text ParserState m Inlines
code1 = B.code . T.pack <$> surrounded (char '@') anyChar'

code2 :: PandocMonad m => ParserT Text ParserState m Inlines
code2 = do
  htmlTag (tagOpen (=="tt") null)
  B.code . T.pack <$> manyTill anyChar' (try $ htmlTag $ tagClose (=="tt"))

-- | Html / CSS attributes
attributes :: PandocMonad m => ParserT Text ParserState m Attr
attributes = foldl (flip ($)) ("",[],[]) <$>
  try (do special <- option id specialAttribute
          attrs <- many attribute
          return (special : attrs))

specialAttribute :: PandocMonad m => ParserT Text ParserState m (Attr -> Attr)
specialAttribute = do
  alignStr <- ("center" <$ char '=') <|>
    ("justify" <$ try (string "<>")) <|>
    ("right" <$ char '>') <|>
    ("left" <$ char '<')
  notFollowedBy spaceChar
  return $ addStyle $ T.pack $ "text-align:" ++ alignStr

attribute :: PandocMonad m => ParserT Text ParserState m (Attr -> Attr)
attribute = try $
  (classIdAttr <|> styleAttr <|> langAttr) <* notFollowedBy spaceChar

classIdAttr :: PandocMonad m => ParserT Text ParserState m (Attr -> Attr)
classIdAttr = try $ do -- (class class #id)
  char '('
  ws <- T.words `fmap` T.pack <$> manyTill anyChar' (char ')')
  case reverse ws of
       []
         -> return $ \(_,_,keyvals) -> ("",[],keyvals)
       ((T.uncons -> Just ('#', ident')):classes')
         -> return $ \(_,_,keyvals) -> (ident',classes',keyvals)
       classes'
         -> return $ \(_,_,keyvals) -> ("",classes',keyvals)

styleAttr :: PandocMonad m => ParserT Text ParserState m (Attr -> Attr)
styleAttr = do
  style <- try $ enclosed (char '{') (char '}') anyChar'
  return $ addStyle $ T.pack style

addStyle :: Text -> Attr -> Attr
addStyle style (id',classes,keyvals) =
  (id',classes,keyvals')
  where keyvals' = ("style", style') : [(k,v) | (k,v) <- keyvals, k /= "style"]
        style' = style <> ";" <> T.concat [v | ("style",v) <- keyvals]

langAttr :: PandocMonad m => ParserT Text ParserState m (Attr -> Attr)
langAttr = do
  lang <- try $ enclosed (char '[') (char ']') alphaNum
  return $ \(id',classes,keyvals) -> (id',classes,("lang",T.pack lang):keyvals)

-- | Parses material surrounded by a parser.
surrounded :: (PandocMonad m, Show t)
           => ParserT Text st m t   -- ^ surrounding parser
           -> ParserT Text st m a   -- ^ content parser (to be used repeatedly)
           -> ParserT Text st m [a]
surrounded border =
  enclosed (border *> notFollowedBy (oneOf " \t\n\r")) (try border)

simpleInline :: PandocMonad m
             => ParserT Text ParserState m t        -- ^ surrounding parser
             -> (Inlines -> Inlines)                  -- ^ Inline constructor
             -> ParserT Text ParserState m Inlines  -- ^ content parser (to be used repeatedly)
simpleInline border construct = try $ do
  notAfterString
  border *> notFollowedBy (oneOf " \t\n\r")
  attr <- attributes
  body <- trimInlines . mconcat <$>
          withQuoteContext InSingleQuote
            (manyTill (notFollowedBy newline >> inline)
             (try border <* notFollowedBy alphaNum))
  return $ construct $
        if attr == nullAttr
           then body
           else B.spanWith attr body

groupedInlineMarkup :: PandocMonad m => ParserT Text ParserState m Inlines
groupedInlineMarkup = try $ do
    char '['
    sp1 <- option mempty $ B.space <$ whitespace
    result <- withQuoteContext InSingleQuote inlineMarkup
    sp2 <- option mempty $ B.space <$ whitespace
    char ']'
    return $ sp1 <> result <> sp2

eof' :: Monad m => ParserT Text s m Char
eof' = '\n' <$ eof