aboutsummaryrefslogtreecommitdiff
path: root/src/Text/Pandoc/Writers/LaTeX.hs
blob: 6a205a7989f488733134f554e2983191caa203d1 (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
{-# LANGUAGE OverloadedStrings   #-}
{-# LANGUAGE LambdaCase          #-}
{-# LANGUAGE TupleSections       #-}
{-# LANGUAGE PatternGuards       #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE ViewPatterns        #-}
{- |
   Module      : Text.Pandoc.Writers.LaTeX
   Copyright   : Copyright (C) 2006-2021 John MacFarlane
   License     : GNU GPL, version 2 or above

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

Conversion of 'Pandoc' format into LaTeX.
-}
module Text.Pandoc.Writers.LaTeX (
    writeLaTeX
  , writeBeamer
  ) where
import Control.Monad.State.Strict
import Data.Char (isDigit)
import Data.List (intersperse, nubBy, (\\))
import Data.Maybe (catMaybes, fromMaybe, isJust, mapMaybe, isNothing)
import qualified Data.Map as M
import Data.Text (Text)
import qualified Data.Text as T
import Network.URI (unEscapeString)
import Text.DocTemplates (FromContext(lookupContext), renderTemplate,
                          Val(..), Context(..))
import Text.Pandoc.BCP47 (Lang (..), getLang, renderLang)
import Text.Pandoc.Class.PandocMonad (PandocMonad, report, toLang)
import Text.Pandoc.Definition
import Text.Pandoc.Highlighting (formatLaTeXBlock, formatLaTeXInline, highlight,
                                 styleToLaTeX)
import Text.Pandoc.ImageSize
import Text.Pandoc.Logging
import Text.Pandoc.Options
import Text.DocLayout
import Text.Pandoc.Shared
import Text.Pandoc.Slides
import Text.Pandoc.Walk (query, walk, walkM)
import Text.Pandoc.Writers.LaTeX.Caption (getCaption)
import Text.Pandoc.Writers.LaTeX.Table (tableToLaTeX)
import Text.Pandoc.Writers.LaTeX.Citation (citationsToNatbib,
                                           citationsToBiblatex)
import Text.Pandoc.Writers.LaTeX.Types (LW, WriterState (..), startingState)
import Text.Pandoc.Writers.LaTeX.Lang (toPolyglossia, toBabel)
import Text.Pandoc.Writers.LaTeX.Util (stringToLaTeX, StringContext(..),
                                       toLabel, inCmd,
                                       wrapDiv, hypertarget, labelFor,
                                       getListingsLanguage, mbBraced)
import Text.Pandoc.Writers.Shared
import qualified Text.Pandoc.Writers.AnnotatedTable as Ann

-- | Convert Pandoc to LaTeX.
writeLaTeX :: PandocMonad m => WriterOptions -> Pandoc -> m Text
writeLaTeX options document =
  evalStateT (pandocToLaTeX options document) $
    startingState options

-- | Convert Pandoc to LaTeX Beamer.
writeBeamer :: PandocMonad m => WriterOptions -> Pandoc -> m Text
writeBeamer options document =
  evalStateT (pandocToLaTeX options document) $
    (startingState options){ stBeamer = True }

pandocToLaTeX :: PandocMonad m
              => WriterOptions -> Pandoc -> LW m Text
pandocToLaTeX options (Pandoc meta blocks) = do
  -- Strip off final 'references' header if --natbib or --biblatex
  let method = writerCiteMethod options
  let blocks' = if method == Biblatex || method == Natbib
                   then case reverse blocks of
                             Div ("refs",_,_) _:xs -> reverse xs
                             _                     -> blocks
                   else blocks
  -- see if there are internal links
  let isInternalLink (Link _ _ (s,_))
        | Just ('#', xs) <- T.uncons s = [xs]
      isInternalLink _                 = []
  modify $ \s -> s{ stInternalLinks = query isInternalLink blocks' }
  let colwidth = if writerWrapText options == WrapAuto
                    then Just $ writerColumns options
                    else Nothing
  metadata <- metaToContext options
              blockListToLaTeX
              (fmap chomp . inlineListToLaTeX)
              meta
  let chaptersClasses = ["memoir","book","report","scrreprt","scrbook","extreport","extbook","tufte-book"]
  let frontmatterClasses = ["memoir","book","scrbook","extbook","tufte-book"]
  -- these have \frontmatter etc.
  beamer <- gets stBeamer
  let documentClass =
        case lookupContext "documentclass" (writerVariables options) `mplus`
              (stringify <$> lookupMeta "documentclass" meta) of
                 Just x -> x
                 Nothing | beamer    -> "beamer"
                         | otherwise -> case writerTopLevelDivision options of
                                          TopLevelPart    -> "book"
                                          TopLevelChapter -> "book"
                                          _               -> "article"
  when (documentClass `elem` chaptersClasses) $
     modify $ \s -> s{ stHasChapters = True }
  case lookupContext "csquotes" (writerVariables options) `mplus`
       (stringify <$> lookupMeta "csquotes" meta) of
     Nothing      -> return ()
     Just "false" -> return ()
     Just _       -> modify $ \s -> s{stCsquotes = True}
  let (blocks'', lastHeader) = if writerCiteMethod options == Citeproc then
                                 (blocks', [])
                               else case reverse blocks' of
                                 Header 1 _ il : _ -> (init blocks', il)
                                 _                 -> (blocks', [])
  blocks''' <- if beamer
                  then toSlides blocks''
                  else return $ makeSections False Nothing blocks''
  main <- blockListToLaTeX blocks'''
  biblioTitle <- inlineListToLaTeX lastHeader
  st <- get
  titleMeta <- stringToLaTeX TextString $ stringify $ docTitle meta
  authorsMeta <- mapM (stringToLaTeX TextString . stringify) $ docAuthors meta
  docLangs <- catMaybes <$>
      mapM (toLang . Just) (ordNub (query (extract "lang") blocks))
  let hasStringValue x = isJust (getField x metadata :: Maybe (Doc Text))
  let geometryFromMargins = mconcat $ intersperse ("," :: Doc Text) $
                            mapMaybe (\(x,y) ->
                                ((x <> "=") <>) <$> getField y metadata)
                              [("lmargin","margin-left")
                              ,("rmargin","margin-right")
                              ,("tmargin","margin-top")
                              ,("bmargin","margin-bottom")
                              ]
  let toPolyObj :: Lang -> Val Text
      toPolyObj lang = MapVal $ Context $
                        M.fromList [ ("name" , SimpleVal $ literal name)
                                   , ("options" , SimpleVal $ literal opts) ]
        where
          (name, opts) = toPolyglossia lang
  mblang <- toLang $ case getLang options meta of
                          Just l -> Just l
                          Nothing | null docLangs -> Nothing
                                  | otherwise     -> Just "en"
  -- we need a default here since lang is used in template conditionals

  let dirs = query (extract "dir") blocks

  let nociteIds = query (\case
                           Cite cs _ -> map citationId cs
                           _         -> [])
                    $ lookupMetaInlines "nocite" meta

  let context  =  defField "toc" (writerTableOfContents options) $
                  defField "toc-depth" (tshow
                                        (writerTOCDepth options -
                                              if stHasChapters st
                                                 then 1
                                                 else 0)) $
                  defField "body" main $
                  defField "title-meta" titleMeta $
                  defField "author-meta"
                        (T.intercalate "; " authorsMeta) $
                  defField "documentclass" documentClass $
                  defField "verbatim-in-note" (stVerbInNote st) $
                  defField "tables" (stTable st) $
                  defField "multirow" (stMultiRow st) $
                  defField "strikeout" (stStrikeout st) $
                  defField "url" (stUrl st) $
                  defField "numbersections" (writerNumberSections options) $
                  defField "lhs" (stLHS st) $
                  defField "graphics" (stGraphics st) $
                  defField "has-chapters" (stHasChapters st) $
                  defField "has-frontmatter" (documentClass `elem` frontmatterClasses) $
                  defField "listings" (writerListings options || stLHS st) $
                  defField "beamer" beamer $
                  (if stHighlighting st
                      then case writerHighlightStyle options of
                                Just sty ->
                                   defField "highlighting-macros"
                                      (T.stripEnd $ styleToLaTeX sty)
                                Nothing -> id
                      else id) $
                  (case writerCiteMethod options of
                         Natbib   -> defField "biblio-title" biblioTitle .
                                     defField "natbib" True .
                                     defField "nocite-ids" nociteIds
                         Biblatex -> defField "biblio-title" biblioTitle .
                                     defField "biblatex" True .
                                     defField "nocite-ids" nociteIds
                         _        -> id) $
                  defField "colorlinks" (any hasStringValue
                           ["citecolor", "urlcolor", "linkcolor", "toccolor",
                            "filecolor"]) $
                  (if null dirs
                     then id
                     else defField "dir" ("ltr" :: Text)) $
                  defField "section-titles" True $
                  defField "csl-refs" (stHasCslRefs st) $
                  defField "geometry" geometryFromMargins $
                  (case T.uncons . render Nothing <$>
                        getField "papersize" metadata of
                      -- uppercase a4, a5, etc.
                      Just (Just ('A', ds))
                        | not (T.null ds) && T.all isDigit ds
                          -> resetField "papersize" ("a" <> ds)
                      _   -> id)
                  metadata
  let context' =
          -- note: lang is used in some conditionals in the template,
          -- so we need to set it if we have any babel/polyglossia:
          maybe id (\l -> defField "lang"
                      (literal $ renderLang l)) mblang
        $ maybe id (\l -> defField "babel-lang"
                      (literal $ toBabel l)) mblang
        $ defField "babel-otherlangs"
             (map (literal . toBabel) docLangs)
        $ defField "babel-newcommands" (vcat $
           map (\(poly, babel) -> literal $
            -- \textspanish and \textgalician are already used by babel
            -- save them as \oritext... and let babel use that
            if poly `elem` ["spanish", "galician"]
               then "\\let\\oritext" <> poly <> "\\text" <> poly <> "\n" <>
                    "\\AddBabelHook{" <> poly <> "}{beforeextras}" <>
                      "{\\renewcommand{\\text" <> poly <> "}{\\oritext"
                      <> poly <> "}}\n" <>
                    "\\AddBabelHook{" <> poly <> "}{afterextras}" <>
                      "{\\renewcommand{\\text" <> poly <> "}[2][]{\\foreignlanguage{"
                      <> poly <> "}{##2}}}"
               else (if poly == "latin" -- see #4161
                        then "\\providecommand{\\textlatin}{}\n\\renewcommand"
                        else "\\newcommand") <> "{\\text" <> poly <>
                    "}[2][]{\\foreignlanguage{" <> babel <> "}{#2}}\n" <>
                    "\\newenvironment{" <> poly <>
                    "}[2][]{\\begin{otherlanguage}{" <>
                    babel <> "}}{\\end{otherlanguage}}"
            )
            -- eliminate duplicates that have same polyglossia name
            $ nubBy (\a b -> fst a == fst b)
            -- find polyglossia and babel names of languages used in the document
            $ map (\l -> (fst $ toPolyglossia l, toBabel l)) docLangs
          )
        $ maybe id (defField "polyglossia-lang" . toPolyObj) mblang
        $ defField "polyglossia-otherlangs"
             (ListVal (map toPolyObj docLangs :: [Val Text]))
        $
                  defField "latex-dir-rtl"
           ((render Nothing <$> getField "dir" context) ==
               Just ("rtl" :: Text)) context
  return $ render colwidth $
    case writerTemplate options of
       Nothing  -> main
       Just tpl -> renderTemplate tpl context'

toSlides :: PandocMonad m => [Block] -> LW m [Block]
toSlides bs = do
  opts <- gets stOptions
  let slideLevel = fromMaybe (getSlideLevel bs) $ writerSlideLevel opts
  let bs' = prepSlides slideLevel bs
  walkM (elementToBeamer slideLevel) $ makeSections False Nothing bs'

-- this creates section slides and marks slides with class "slide","block"
elementToBeamer :: PandocMonad m => Int -> Block -> LW m Block
elementToBeamer slideLevel (Div (ident,"section":dclasses,dkvs)
                              xs@(h@(Header lvl _ _) : ys))
  | lvl >  slideLevel
    = return $ Div (ident,"block":dclasses,dkvs) xs
  | lvl <  slideLevel
    = do let isSlide (Div (_,"slide":_,_) _)   = True
             isSlide (Div (_,"section":_,_) _) = True
             isSlide _                         = False
         let (titleBs, slideBs) = break isSlide ys
         return $
           if null titleBs
              then Div (ident,"section":dclasses,dkvs) xs
              else Div (ident,"section":dclasses,dkvs)
                    (h : Div ("","slide":dclasses,dkvs) (h:titleBs) : slideBs)
  | otherwise
    = return $ Div (ident,"slide":dclasses,dkvs) xs
elementToBeamer _ x = return x

isListBlock :: Block -> Bool
isListBlock (BulletList _)     = True
isListBlock (OrderedList _ _)  = True
isListBlock (DefinitionList _) = True
isListBlock _                  = False

-- | Convert Pandoc block element to LaTeX.
blockToLaTeX :: PandocMonad m
             => Block     -- ^ Block to convert
             -> LW m (Doc Text)
blockToLaTeX Null = return empty
blockToLaTeX (Div attr@(identifier,"block":_,_) (Header _ _ ils : bs)) = do
  ref <- toLabel identifier
  let anchor = if T.null identifier
                  then empty
                  else cr <> "\\protect\\hypertarget" <>
                       braces (literal ref) <> braces empty
  title' <- inlineListToLaTeX ils
  contents <- blockListToLaTeX bs
  wrapDiv attr $ ("\\begin{block}" <> braces title' <> anchor) $$
                 contents $$ "\\end{block}"
blockToLaTeX (Div (identifier,"slide":dclasses,dkvs)
               (Header _ (_,hclasses,hkvs) ils : bs)) = do
  -- note: [fragile] is required or verbatim breaks
  let hasCodeBlock (CodeBlock _ _) = [True]
      hasCodeBlock _               = []
  let hasCode (Code _ _) = [True]
      hasCode _          = []
  let classes = ordNub $ dclasses ++ hclasses
  let kvs = ordNub $ dkvs ++ hkvs
  let fragile = "fragile" `elem` classes ||
                not (null $ query hasCodeBlock bs ++ query hasCode bs)
  let frameoptions = ["allowdisplaybreaks", "allowframebreaks", "fragile",
                      "b", "c", "t", "environment",
                      "label", "plain", "shrink", "standout",
                      "noframenumbering"]
  let optionslist = ["fragile" | fragile
                               , isNothing (lookup "fragile" kvs)
                               , "fragile" `notElem` classes] ++
                    [k | k <- classes, k `elem` frameoptions] ++
                    [k <> "=" <> v | (k,v) <- kvs, k `elem` frameoptions]
  let options = if null optionslist
                   then empty
                   else brackets (literal (T.intercalate "," optionslist))
  slideTitle <- if ils == [Str "\0"] -- marker for hrule
                   then return empty
                   else braces <$> inlineListToLaTeX ils
  ref <- toLabel identifier
  let slideAnchor = if T.null identifier
                       then empty
                       else cr <> "\\protect\\hypertarget" <>
                            braces (literal ref) <> braces empty
  contents <- blockListToLaTeX bs >>= wrapDiv (identifier,classes,kvs)
  return $ ("\\begin{frame}" <> options <> slideTitle <> slideAnchor) $$
             contents $$ "\\end{frame}"
blockToLaTeX (Div (identifier@(T.uncons -> Just (_,_)),dclasses,dkvs)
               (Header lvl ("",hclasses,hkvs) ils : bs)) =
  -- move identifier from div to header
  blockToLaTeX (Div ("",dclasses,dkvs)
               (Header lvl (identifier,hclasses,hkvs) ils : bs))
blockToLaTeX (Div (identifier,classes,kvs) bs) = do
  beamer <- gets stBeamer
  oldIncremental <- gets stIncremental
  if beamer && "incremental" `elem` classes
     then modify $ \st -> st{ stIncremental = True }
     else when (beamer && "nonincremental" `elem` classes) $
             modify $ \st -> st { stIncremental = False }
  result <- if identifier == "refs" || -- <- for backwards compatibility
               "csl-bib-body" `elem` classes
               then do
                 modify $ \st -> st{ stHasCslRefs = True }
                 inner <- blockListToLaTeX bs
                 return $ "\\begin{CSLReferences}" <>
                          (if "hanging-indent" `elem` classes
                              then braces "1"
                              else braces "0") <>
                          (case lookup "entry-spacing" kvs of
                             Nothing -> braces "0"
                             Just s  -> braces (literal s))
                          $$ inner
                          $+$ "\\end{CSLReferences}"
               else blockListToLaTeX bs
  modify $ \st -> st{ stIncremental = oldIncremental }
  linkAnchor' <- hypertarget True identifier empty
  -- see #2704 for the motivation for adding \leavevmode
  -- and #7078 for \vadjust pre
  let linkAnchor =
        case bs of
          Para _ : _
            | not (isEmpty linkAnchor')
              -> "\\leavevmode\\vadjust pre{" <> linkAnchor' <> "}%"
          _ -> linkAnchor'
      wrapNotes txt = if beamer && "notes" `elem` classes
                         then "\\note" <> braces txt -- speaker notes
                         else linkAnchor $$ txt
  wrapNotes <$> wrapDiv (identifier,classes,kvs) result
blockToLaTeX (Plain lst) =
  inlineListToLaTeX lst
-- title beginning with fig: indicates that the image is a figure
blockToLaTeX (Para [Image attr@(ident, _, _) txt (src,tgt)])
  | Just tit <- T.stripPrefix "fig:" tgt
  = do
      (capt, captForLof, footnotes) <- getCaption inlineListToLaTeX True txt
      lab <- labelFor ident
      let caption = "\\caption" <> captForLof <> braces capt <> lab
      img <- inlineToLaTeX (Image attr txt (src,tit))
      innards <- hypertarget True ident $
                   "\\centering" $$ img $$ caption <> cr
      let figure = cr <> "\\begin{figure}" $$ innards $$ "\\end{figure}"
      st <- get
      return $ (if stInMinipage st
                 -- can't have figures in notes or minipage (here, table cell)
                 -- http://www.tex.ac.uk/FAQ-ouparmd.html
                then cr <> "\\begin{center}" $$ img $+$ capt $$
                       "\\end{center}"
                else figure) $$ footnotes
-- . . . indicates pause in beamer slides
blockToLaTeX (Para [Str ".",Space,Str ".",Space,Str "."]) = do
  beamer <- gets stBeamer
  if beamer
     then blockToLaTeX (RawBlock "latex" "\\pause")
     else inlineListToLaTeX [Str ".",Space,Str ".",Space,Str "."]
blockToLaTeX (Para lst) =
  inlineListToLaTeX lst
blockToLaTeX (LineBlock lns) =
  blockToLaTeX $ linesToPara lns
blockToLaTeX (BlockQuote lst) = do
  beamer <- gets stBeamer
  case lst of
       [b] | beamer && isListBlock b -> do
         oldIncremental <- gets stIncremental
         modify $ \s -> s{ stIncremental = not oldIncremental }
         result <- blockToLaTeX b
         modify $ \s -> s{ stIncremental = oldIncremental }
         return result
       _ -> do
         oldInQuote <- gets stInQuote
         modify (\s -> s{stInQuote = True})
         contents <- blockListToLaTeX lst
         modify (\s -> s{stInQuote = oldInQuote})
         return $ "\\begin{quote}" $$ contents $$ "\\end{quote}"
blockToLaTeX (CodeBlock (identifier,classes,keyvalAttr) str) = do
  opts <- gets stOptions
  lab <- labelFor identifier
  linkAnchor' <- hypertarget True identifier lab
  let linkAnchor = if isEmpty linkAnchor'
                      then empty
                      else linkAnchor' <> "%"
  let lhsCodeBlock = do
        modify $ \s -> s{ stLHS = True }
        return $ flush (linkAnchor $$ "\\begin{code}" $$ literal str $$
                            "\\end{code}") $$ cr
  let rawCodeBlock = do
        st <- get
        env <- if stInNote st
                  then modify (\s -> s{ stVerbInNote = True }) >>
                       return "Verbatim"
                  else return "verbatim"
        return $ flush (linkAnchor $$ literal ("\\begin{" <> env <> "}") $$
                 literal str $$ literal ("\\end{" <> env <> "}")) <> cr
  let listingsCodeBlock = do
        st <- get
        ref <- toLabel identifier
        kvs <- mapM (\(k,v) -> (k,) <$>
                       stringToLaTeX TextString v) keyvalAttr
        let params = if writerListings (stOptions st)
                     then (case getListingsLanguage classes of
                                Just l  -> [ "language=" <> mbBraced l ]
                                Nothing -> []) ++
                          [ "numbers=left" | "numberLines" `elem` classes
                             || "number" `elem` classes
                             || "number-lines" `elem` classes ] ++
                          [ (if key == "startFrom"
                                then "firstnumber"
                                else key) <> "=" <> mbBraced attr |
                                (key,attr) <- kvs,
                                key `notElem` ["exports", "tangle", "results"]
                                -- see #4889
                          ] ++
                          ["label=" <> ref | not (T.null identifier)]

                     else []
            printParams
                | null params = empty
                | otherwise   = brackets $ hcat (intersperse ", "
                      (map literal params))
        return $ flush ("\\begin{lstlisting}" <> printParams $$ literal str $$
                 "\\end{lstlisting}") $$ cr
  let highlightedCodeBlock =
        case highlight (writerSyntaxMap opts)
                 formatLaTeXBlock ("",classes,keyvalAttr) str of
               Left msg -> do
                 unless (T.null msg) $
                   report $ CouldNotHighlight msg
                 rawCodeBlock
               Right h -> do
                  st <- get
                  when (stInNote st) $ modify (\s -> s{ stVerbInNote = True })
                  modify (\s -> s{ stHighlighting = True })
                  return (flush $ linkAnchor $$ text (T.unpack h))
  case () of
     _ | isEnabled Ext_literate_haskell opts && "haskell" `elem` classes &&
         "literate" `elem` classes           -> lhsCodeBlock
       | writerListings opts                 -> listingsCodeBlock
       | not (null classes) && isJust (writerHighlightStyle opts)
                                             -> highlightedCodeBlock
       | otherwise                           -> rawCodeBlock
blockToLaTeX b@(RawBlock f x) = do
  beamer <- gets stBeamer
  if f == Format "latex" || f == Format "tex" ||
       (f == Format "beamer" && beamer)
     then return $ literal x
     else do
       report $ BlockNotRendered b
       return empty
blockToLaTeX (BulletList []) = return empty  -- otherwise latex error
blockToLaTeX (BulletList lst) = do
  incremental <- gets stIncremental
  isFirstInDefinition <- gets stIsFirstInDefinition
  beamer <- gets stBeamer
  let inc = if beamer && incremental then "[<+->]" else ""
  items <- mapM listItemToLaTeX lst
  let spacing = if isTightList lst
                   then text "\\tightlist"
                   else empty
  return $ text ("\\begin{itemize}" <> inc) $$
             spacing $$
             -- force list at beginning of definition to start on new line
             (if isFirstInDefinition then "\\item[]" else mempty) $$
             vcat items $$
             "\\end{itemize}"
blockToLaTeX (OrderedList _ []) = return empty -- otherwise latex error
blockToLaTeX (OrderedList (start, numstyle, numdelim) lst) = do
  st <- get
  let inc = if stBeamer st && stIncremental st then "[<+->]" else ""
  let oldlevel = stOLLevel st
  isFirstInDefinition <- gets stIsFirstInDefinition
  put $ st {stOLLevel = oldlevel + 1}
  items <- mapM listItemToLaTeX lst
  modify (\s -> s {stOLLevel = oldlevel})
  let beamer = stBeamer st
  let tostyle x = case numstyle of
                       Decimal      -> "\\arabic" <> braces x
                       UpperRoman   -> "\\Roman" <> braces x
                       LowerRoman   -> "\\roman" <> braces x
                       UpperAlpha   -> "\\Alph" <> braces x
                       LowerAlpha   -> "\\alph" <> braces x
                       Example      -> "\\arabic" <> braces x
                       DefaultStyle -> "\\arabic" <> braces x
  let todelim x = case numdelim of
                       OneParen  -> x <> ")"
                       TwoParens -> parens x
                       Period    -> x <> "."
                       _         -> x <> "."
  let exemplar = case numstyle of
                       Decimal      -> "1"
                       UpperRoman   -> "I"
                       LowerRoman   -> "i"
                       UpperAlpha   -> "A"
                       LowerAlpha   -> "a"
                       Example      -> "1"
                       DefaultStyle -> "1"
  let enum = literal $ "enum" <> T.toLower (toRomanNumeral oldlevel)
  let stylecommand
        | numstyle == DefaultStyle && numdelim == DefaultDelim = empty
        | beamer && numstyle == Decimal && numdelim == Period = empty
        | beamer = brackets (todelim exemplar)
        | otherwise = "\\def" <> "\\label" <> enum <>
          braces (todelim $ tostyle enum)
  let resetcounter = if start == 1 || oldlevel > 4
                        then empty
                        else "\\setcounter" <> braces enum <>
                              braces (text $ show $ start - 1)
  let spacing = if isTightList lst
                   then text "\\tightlist"
                   else empty
  return $ text ("\\begin{enumerate}" <> inc)
         $$ stylecommand
         $$ resetcounter
         $$ spacing
         -- force list at beginning of definition to start on new line
         $$ (if isFirstInDefinition then "\\item[]" else mempty)
         $$ vcat items
         $$ "\\end{enumerate}"
blockToLaTeX (DefinitionList []) = return empty
blockToLaTeX (DefinitionList lst) = do
  incremental <- gets stIncremental
  beamer <- gets stBeamer
  let inc = if beamer && incremental then "[<+->]" else ""
  items <- mapM defListItemToLaTeX lst
  let spacing = if all (isTightList . snd) lst
                   then text "\\tightlist"
                   else empty
  return $ text ("\\begin{description}" <> inc) $$ spacing $$ vcat items $$
               "\\end{description}"
blockToLaTeX HorizontalRule =
            return
  "\\begin{center}\\rule{0.5\\linewidth}{0.5pt}\\end{center}"
blockToLaTeX (Header level (id',classes,_) lst) = do
  modify $ \s -> s{stInHeading = True}
  hdr <- sectionHeader classes id' level lst
  modify $ \s -> s{stInHeading = False}
  return hdr
blockToLaTeX (Table attr blkCapt specs thead tbodies tfoot) =
  tableToLaTeX inlineListToLaTeX blockListToLaTeX
               (Ann.toTable attr blkCapt specs thead tbodies tfoot)

blockListToLaTeX :: PandocMonad m => [Block] -> LW m (Doc Text)
blockListToLaTeX lst =
  vsep `fmap` mapM (\b -> setEmptyLine True >> blockToLaTeX b) lst

listItemToLaTeX :: PandocMonad m => [Block] -> LW m (Doc Text)
listItemToLaTeX lst
  -- we need to put some text before a header if it's the first
  -- element in an item. This will look ugly in LaTeX regardless, but
  -- this will keep the typesetter from throwing an error.
  | (Header{} :_) <- lst =
    (text "\\item ~" $$) . nest 2 <$> blockListToLaTeX lst
  | Plain (Str "☐":Space:is) : bs <- lst = taskListItem False is bs
  | Plain (Str "☒":Space:is) : bs <- lst = taskListItem True  is bs
  | Para  (Str "☐":Space:is) : bs <- lst = taskListItem False is bs
  | Para  (Str "☒":Space:is) : bs <- lst = taskListItem True  is bs
  | otherwise = (text "\\item" $$) . nest 2 <$> blockListToLaTeX lst
  where
    taskListItem checked is bs = do
      let checkbox  = if checked
                      then "$\\boxtimes$"
                      else "$\\square$"
      isContents <- inlineListToLaTeX is
      bsContents <- blockListToLaTeX bs
      return $ "\\item" <> brackets checkbox
        $$ nest 2 (isContents $+$ bsContents)

defListItemToLaTeX :: PandocMonad m => ([Inline], [[Block]]) -> LW m (Doc Text)
defListItemToLaTeX (term, defs) = do
    -- needed to turn off 'listings' because it breaks inside \item[...]:
    modify $ \s -> s{stInItem = True}
    term' <- inlineListToLaTeX term
    modify $ \s -> s{stInItem = False}
    -- put braces around term if it contains an internal link,
    -- since otherwise we get bad bracket interactions: \item[\hyperref[..]
    let isInternalLink (Link _ _ (src,_))
          | Just ('#', _) <- T.uncons src = True
        isInternalLink _                  = False
    let term'' = if any isInternalLink term
                    then braces term'
                    else term'
    def'  <- case concat defs of
               [] -> return mempty
               (x:xs) -> do
                 modify $ \s -> s{stIsFirstInDefinition = True }
                 firstitem <- blockToLaTeX x
                 modify $ \s -> s{stIsFirstInDefinition = False }
                 rest <- blockListToLaTeX xs
                 return $ firstitem $+$ rest
    return $ case defs of
     ((Header{} : _) : _)    ->
       "\\item" <> brackets term'' <> " ~ " $$ def'
     ((CodeBlock{} : _) : _) -> -- see #4662
       "\\item" <> brackets term'' <> " ~ " $$ def'
     _                       ->
       "\\item" <> brackets term'' $$ def'

-- | Craft the section header, inserting the secton reference, if supplied.
sectionHeader :: PandocMonad m
              => [Text]  -- classes
              -> Text
              -> Int
              -> [Inline]
              -> LW m (Doc Text)
sectionHeader classes ident level lst = do
  let unnumbered = "unnumbered" `elem` classes
  let unlisted = "unlisted" `elem` classes
  txt <- inlineListToLaTeX lst
  plain <- stringToLaTeX TextString $ T.concat $ map stringify lst
  let removeInvalidInline (Note _)             = []
      removeInvalidInline (Span (id', _, _) _) | not (T.null id') = []
      removeInvalidInline Image{}            = []
      removeInvalidInline x                    = [x]
  let lstNoNotes = foldr (mappend . (\x -> walkM removeInvalidInline x)) mempty lst
  txtNoNotes <- inlineListToLaTeX lstNoNotes
  -- footnotes in sections don't work (except for starred variants)
  -- unless you specify an optional argument:
  -- \section[mysec]{mysec\footnote{blah}}
  optional <- if unnumbered || lstNoNotes == lst || null lstNoNotes
                 then return empty
                 else
                   return $ brackets txtNoNotes
  let contents = if render Nothing txt == plain
                    then braces txt
                    else braces (text "\\texorpdfstring"
                         <> braces txt
                         <> braces (literal plain))
  book <- gets stHasChapters
  opts <- gets stOptions
  let topLevelDivision = if book && writerTopLevelDivision opts == TopLevelDefault
                         then TopLevelChapter
                         else writerTopLevelDivision opts
  beamer <- gets stBeamer
  let level' = if beamer &&
                  topLevelDivision `elem` [TopLevelPart, TopLevelChapter]
               -- beamer has parts but no chapters
               then if level == 1 then -1 else level - 1
               else case topLevelDivision of
                      TopLevelPart    -> level - 2
                      TopLevelChapter -> level - 1
                      TopLevelSection -> level
                      TopLevelDefault -> level
  let sectionType = case level' of
                          -1 -> "part"
                          0  -> "chapter"
                          1  -> "section"
                          2  -> "subsection"
                          3  -> "subsubsection"
                          4  -> "paragraph"
                          5  -> "subparagraph"
                          _  -> ""
  inQuote <- gets stInQuote
  let prefix = if inQuote && level' >= 4
                  then text "\\mbox{}%"
                  -- needed for \paragraph, \subparagraph in quote environment
                  -- see http://tex.stackexchange.com/questions/169830/
                  else empty
  lab <- labelFor ident
  let star = if unnumbered then text "*" else empty
  let stuffing = star <> optional <> contents
  stuffing' <- hypertarget True ident $
                  text ('\\':sectionType) <> stuffing <> lab
  return $ if level' > 5
              then txt
              else prefix $$ stuffing'
                   $$ if unnumbered && not unlisted
                         then "\\addcontentsline{toc}" <>
                                braces (text sectionType) <>
                                braces txtNoNotes
                         else empty

-- | Convert list of inline elements to LaTeX.
inlineListToLaTeX :: PandocMonad m
                  => [Inline]  -- ^ Inlines to convert
                  -> LW m (Doc Text)
inlineListToLaTeX lst = hcat <$>
  mapM inlineToLaTeX (fixLineInitialSpaces . fixInitialLineBreaks $ lst)
    -- nonbreaking spaces (~) in LaTeX don't work after line breaks,
    -- so we turn nbsps after hard breaks to \hspace commands.
    -- this is mostly used in verse.
 where fixLineInitialSpaces [] = []
       fixLineInitialSpaces (LineBreak : Str s : xs)
         | Just ('\160', _) <- T.uncons s
         = LineBreak : fixNbsps s <> fixLineInitialSpaces xs
       fixLineInitialSpaces (x:xs) = x : fixLineInitialSpaces xs
       fixNbsps s = let (ys,zs) = T.span (=='\160') s
                    in  replicate (T.length ys) hspace <> [Str zs]
       hspace = RawInline "latex" "\\hspace*{0.333em}"
       -- We need \hfill\break for a line break at the start
       -- of a paragraph. See #5591.
       fixInitialLineBreaks (LineBreak:xs) =
         RawInline (Format "latex") "\\hfill\\break\n" :
           fixInitialLineBreaks xs
       fixInitialLineBreaks xs = xs

-- | Convert inline element to LaTeX
inlineToLaTeX :: PandocMonad m
              => Inline    -- ^ Inline to convert
              -> LW m (Doc Text)
inlineToLaTeX (Span (id',classes,kvs) ils) = do
  linkAnchor <- hypertarget False id' empty
  lang <- toLang $ lookup "lang" kvs
  let classToCmd "csl-no-emph" = Just "textup"
      classToCmd "csl-no-strong" = Just "textnormal"
      classToCmd "csl-no-smallcaps" = Just "textnormal"
      classToCmd "csl-block" = Just "CSLBlock"
      classToCmd "csl-left-margin" = Just "CSLLeftMargin"
      classToCmd "csl-right-inline" = Just "CSLRightInline"
      classToCmd "csl-indent" = Just "CSLIndent"
      classToCmd _ = Nothing
      kvToCmd ("dir","rtl") = Just "RL"
      kvToCmd ("dir","ltr") = Just "LR"
      kvToCmd _ = Nothing
      langCmds =
        case lang of
           Just lng -> let (l, o) = toPolyglossia lng
                           ops = if T.null o then "" else "[" <> o <> "]"
                       in  ["text" <> l <> ops]
           Nothing  -> []
  let cmds = mapMaybe classToCmd classes ++ mapMaybe kvToCmd kvs ++ langCmds
  contents <- inlineListToLaTeX ils
  return $
    (case classes of
              ["csl-block"] -> (cr <>)
              ["csl-left-margin"] -> (cr <>)
              ["csl-right-inline"] -> (cr <>)
              ["csl-indent"] -> (cr <>)
              _ -> id) $
    (if T.null id'
        then empty
        else "\\protect" <> linkAnchor) <>
    (if null cmds
        then braces contents
        else foldr inCmd contents cmds)
inlineToLaTeX (Emph lst) = inCmd "emph" <$> inlineListToLaTeX lst
inlineToLaTeX (Underline lst) = inCmd "underline" <$> inlineListToLaTeX lst
inlineToLaTeX (Strong lst) = inCmd "textbf" <$> inlineListToLaTeX lst
inlineToLaTeX (Strikeout lst) = do
  -- we need to protect VERB in an mbox or we get an error
  -- see #1294
  -- with regular texttt we don't get an error, but we get
  -- incorrect results if there is a space, see #5529
  contents <- inlineListToLaTeX $ walk (concatMap protectCode) lst
  modify $ \s -> s{ stStrikeout = True }
  return $ inCmd "sout" contents
inlineToLaTeX (Superscript lst) =
  inCmd "textsuperscript" <$> inlineListToLaTeX lst
inlineToLaTeX (Subscript lst) =
  inCmd "textsubscript" <$> inlineListToLaTeX lst
inlineToLaTeX (SmallCaps lst) =
  inCmd "textsc"<$> inlineListToLaTeX lst
inlineToLaTeX (Cite cits lst) = do
  st <- get
  let opts = stOptions st
  case writerCiteMethod opts of
     Natbib   -> citationsToNatbib inlineListToLaTeX cits
     Biblatex -> citationsToBiblatex inlineListToLaTeX cits
     _        -> inlineListToLaTeX lst

inlineToLaTeX (Code (_,classes,kvs) str) = do
  opts <- gets stOptions
  inHeading <- gets stInHeading
  inItem <- gets stInItem
  let listingsCode = do
        let listingsopts = (case getListingsLanguage classes of
                                Just l  -> (("language", mbBraced l):)
                                Nothing -> id)
                           [(k,v) | (k,v) <- kvs
                                  , k `notElem` ["exports","tangle","results"]]
        let listingsopt = if null listingsopts
                             then ""
                             else "[" <>
                                  T.intercalate ", "
                                  (map (\(k,v) -> k <> "=" <> v)
                                   listingsopts) <> "]"
        inNote <- gets stInNote
        when inNote $ modify $ \s -> s{ stVerbInNote = True }
        let chr = case "!\"'()*,-./:;?@" \\ T.unpack str of
                       (c:_) -> c
                       []    -> '!'
        let str' = escapeStringUsing (backslashEscapes "\\{}%~_&#^") str
        -- we always put lstinline in a dummy 'passthrough' command
        -- (defined in the default template) so that we don't have
        -- to change the way we escape characters depending on whether
        -- the lstinline is inside another command.  See #1629:
        return $ literal $ "\\passthrough{\\lstinline" <>
                        listingsopt <> T.singleton chr <> str' <> T.singleton chr <> "}"
  let rawCode = liftM (literal . (\s -> "\\texttt{" <> escapeSpaces s <> "}"))
                 $ stringToLaTeX CodeString str
                where escapeSpaces = T.concatMap
                         (\c -> if c == ' ' then "\\ " else T.singleton c)
  let highlightCode =
        case highlight (writerSyntaxMap opts)
                 formatLaTeXInline ("",classes,[]) str of
               Left msg -> do
                 unless (T.null msg) $ report $ CouldNotHighlight msg
                 rawCode
               Right h -> modify (\st -> st{ stHighlighting = True }) >>
                          return (text (T.unpack h))
  case () of
     _ | inHeading || inItem  -> rawCode  -- see #5574
       | writerListings opts  -> listingsCode
       | isJust (writerHighlightStyle opts) && not (null classes)
                              -> highlightCode
       | otherwise            -> rawCode
inlineToLaTeX (Quoted qt lst) = do
  contents <- inlineListToLaTeX lst
  csquotes <- liftM stCsquotes get
  opts <- gets stOptions
  if csquotes
     then return $ case qt of
               DoubleQuote -> "\\enquote" <> braces contents
               SingleQuote -> "\\enquote*" <> braces contents
     else do
       let s1 = if not (null lst) && isQuoted (head lst)
                   then "\\,"
                   else empty
       let s2 = if not (null lst) && isQuoted (last lst)
                   then "\\,"
                   else empty
       let inner = s1 <> contents <> s2
       return $ case qt of
                DoubleQuote ->
                   if isEnabled Ext_smart opts
                      then text "``" <> inner <> text "''"
                      else char '\x201C' <> inner <> char '\x201D'
                SingleQuote ->
                   if isEnabled Ext_smart opts
                      then char '`' <> inner <> char '\''
                      else char '\x2018' <> inner <> char '\x2019'
    where
      isQuoted (Quoted _ _) = True
      isQuoted _            = False
inlineToLaTeX (Str str) = do
  setEmptyLine False
  liftM literal $ stringToLaTeX TextString str
inlineToLaTeX (Math InlineMath str) = do
  setEmptyLine False
  return $ "\\(" <> literal (handleMathComment str) <> "\\)"
inlineToLaTeX (Math DisplayMath str) = do
  setEmptyLine False
  return $ "\\[" <> literal (handleMathComment str) <> "\\]"
inlineToLaTeX il@(RawInline f str) = do
  beamer <- gets stBeamer
  if f == Format "latex" || f == Format "tex" ||
        (f == Format "beamer" && beamer)
     then do
       setEmptyLine False
       return $ literal str
     else do
       report $ InlineNotRendered il
       return empty
inlineToLaTeX LineBreak = do
  emptyLine <- gets stEmptyLine
  setEmptyLine True
  return $ (if emptyLine then "~" else "") <> "\\\\" <> cr
inlineToLaTeX SoftBreak = do
  wrapText <- gets (writerWrapText . stOptions)
  case wrapText of
       WrapAuto     -> return space
       WrapNone     -> return space
       WrapPreserve -> return cr
inlineToLaTeX Space = return space
inlineToLaTeX (Link (id',_,_) txt (src,_)) =
   (case T.uncons src of
     Just ('#', ident) -> do
        contents <- inlineListToLaTeX txt
        lab <- toLabel ident
        return $ text "\\protect\\hyperlink" <> braces (literal lab) <> braces contents
     _ -> case txt of
          [Str x] | unEscapeString (T.unpack x) == unEscapeString (T.unpack src) ->  -- autolink
               do modify $ \s -> s{ stUrl = True }
                  src' <- stringToLaTeX URLString (escapeURI src)
                  return $ literal $ "\\url{" <> src' <> "}"
          [Str x] | Just rest <- T.stripPrefix "mailto:" src,
                    unEscapeString (T.unpack x) == unEscapeString (T.unpack rest) -> -- email autolink
               do modify $ \s -> s{ stUrl = True }
                  src' <- stringToLaTeX URLString (escapeURI src)
                  contents <- inlineListToLaTeX txt
                  return $ "\\href" <> braces (literal src') <>
                     braces ("\\nolinkurl" <> braces contents)
          _ -> do contents <- inlineListToLaTeX txt
                  src' <- stringToLaTeX URLString (escapeURI src)
                  return $ literal ("\\href{" <> src' <> "}{") <>
                           contents <> char '}')
     >>= (if T.null id'
             then return
             else \x -> do
               linkAnchor <- hypertarget False id' x
               return ("\\protect" <> linkAnchor))
inlineToLaTeX il@(Image _ _ (src, _))
  | Just _ <- T.stripPrefix "data:" src = do
      report $ InlineNotRendered il
      return empty
inlineToLaTeX (Image attr _ (source, _)) = do
  setEmptyLine False
  modify $ \s -> s{ stGraphics = True }
  opts <- gets stOptions
  let showDim dir = let d = text (show dir) <> "="
                    in case dimension dir attr of
                         Just (Pixel a)   ->
                           [d <> literal (showInInch opts (Pixel a)) <> "in"]
                         Just (Percent a) ->
                           [d <> literal (showFl (a / 100)) <>
                             case dir of
                                Width  -> "\\textwidth"
                                Height -> "\\textheight"
                           ]
                         Just dim         ->
                           [d <> text (show dim)]
                         Nothing          ->
                           case dir of
                                Width | isJust (dimension Height attr) ->
                                  [d <> "\\textwidth"]
                                Height | isJust (dimension Width attr) ->
                                  [d <> "\\textheight"]
                                _ -> []
      dimList = showDim Width <> showDim Height
      dims = if null dimList
                then empty
                else brackets $ mconcat (intersperse "," dimList)
      source' = if isURI source
                   then source
                   else T.pack $ unEscapeString $ T.unpack source
  source'' <- stringToLaTeX URLString source'
  inHeading <- gets stInHeading
  return $
    (if inHeading then "\\protect\\includegraphics" else "\\includegraphics") <>
    dims <> braces (literal source'')
inlineToLaTeX (Note contents) = do
  setEmptyLine False
  externalNotes <- gets stExternalNotes
  modify (\s -> s{stInNote = True, stExternalNotes = True})
  contents' <- blockListToLaTeX contents
  modify (\s -> s {stInNote = False, stExternalNotes = externalNotes})
  let optnl = case reverse contents of
                   (CodeBlock _ _ : _) -> cr
                   _                   -> empty
  let noteContents = nest 2 contents' <> optnl
  beamer <- gets stBeamer
  -- in beamer slides, display footnote from current overlay forward
  let beamerMark = if beamer
                      then text "<.->"
                      else empty
  if externalNotes
     then do
       modify $ \st -> st{ stNotes = noteContents : stNotes st }
       return "\\footnotemark{}"
       -- note: a \n before } needed when note ends with a Verbatim environment
       else return $ "\\footnote" <> beamerMark <> braces noteContents

-- A comment at the end of math needs to be followed by a newline,
-- or the closing delimiter gets swallowed.
handleMathComment :: Text -> Text
handleMathComment s =
  let (_, ys) = T.break (\c -> c == '\n' || c == '%') $ T.reverse s -- no T.breakEnd
  in  case T.uncons ys of
        Just ('%', ys') -> case T.uncons ys' of
          Just ('\\', _) -> s
          _              -> s <> "\n"
        _                -> s

protectCode :: Inline -> [Inline]
protectCode x@(Code _ _) = [ltx "\\mbox{" , x , ltx "}"]
  where ltx = RawInline (Format "latex")
protectCode x = [x]

setEmptyLine :: PandocMonad m => Bool -> LW m ()
setEmptyLine b = modify $ \st -> st{ stEmptyLine = b }

-- Extract a key from divs and spans
extract :: Text -> Block -> [Text]
extract key (Div attr _)     = lookKey key attr
extract key (Plain ils)      = query (extractInline key) ils
extract key (Para ils)       = query (extractInline key) ils
extract key (Header _ _ ils) = query (extractInline key) ils
extract _ _                  = []

-- Extract a key from spans
extractInline :: Text -> Inline -> [Text]
extractInline key (Span attr _) = lookKey key attr
extractInline _ _               = []

-- Look up a key in an attribute and give a list of its values
lookKey :: Text -> Attr -> [Text]
lookKey key (_,_,kvs) =  maybe [] T.words $ lookup key kvs