aboutsummaryrefslogtreecommitdiff
path: root/src/Text/Pandoc/App.hs
blob: a4f48e33603ef796a3e9c01b4387a358db8eca82 (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
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
{-# LANGUAGE CPP, TupleSections, ScopedTypeVariables, PatternGuards #-}
{-
Copyright (C) 2006-2016 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.App
   Copyright   : Copyright (C) 2006-2016 John MacFarlane
   License     : GNU GPL, version 2 or above

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

Does a pandoc conversion based on command-line options.
-}
module Text.Pandoc.App (
            convertWithOpts
          , Opt(..)
          , defaultOpts
          , parseOptions
          , options
          ) where
import Text.Pandoc
import Text.Pandoc.Builder (setMeta)
import Text.Pandoc.PDF (makePDF)
import Text.Pandoc.Walk (walk)
import Text.Pandoc.Shared ( tabFilter, readDataFileUTF8,
                            headerShift, err, openURL, safeRead,
                            readDataFile )
import Text.Pandoc.MediaBag ( mediaDirectory, extractMediaBag, MediaBag )
import Text.Pandoc.XML ( toEntities )
import Text.Pandoc.Highlighting (highlightingStyles)
import Text.Pandoc.SelfContained ( makeSelfContained )
import Text.Pandoc.Process (pipeProcess)
import Skylighting ( Style, defaultSyntaxMap, Syntax(..) )
import Text.Printf
import System.Environment ( getEnvironment, getProgName, getArgs )
import Control.Applicative ((<|>))
import System.Exit ( ExitCode (..), exitSuccess )
import System.FilePath
import Data.Char ( toLower, toUpper )
import Data.List ( intercalate, isPrefixOf, isSuffixOf, sort )
import System.Directory ( getAppUserDataDirectory, findExecutable,
                          doesFileExist, Permissions(..), getPermissions )
import System.IO ( stdout, stderr )
import System.IO.Error ( isDoesNotExistError )
import qualified Control.Exception as E
import Control.Exception.Extensible ( throwIO )
import qualified Text.Pandoc.UTF8 as UTF8
import Control.Monad
import Control.Monad.Trans
import Data.Maybe (fromMaybe, isNothing, isJust)
import Data.Foldable (foldrM)
import Network.URI (parseURI, isURI, URI(..))
import qualified Data.ByteString.Lazy as B
import qualified Data.ByteString as BS
import qualified Data.Map as M
import Data.Aeson (eitherDecode', encode)
import Data.Yaml (decode)
import qualified Data.Yaml as Yaml
import qualified Data.Text as T
import System.Console.GetOpt
import Text.Pandoc.Class (withMediaBag, PandocIO, getLog)
import Paths_pandoc (getDataDir)
#ifndef _WINDOWS
import System.Posix.Terminal (queryTerminal)
import System.Posix.IO (stdOutput)
#endif

parseOptions :: [OptDescr (Opt -> IO Opt)] -> Opt -> IO Opt
parseOptions options' defaults = do
  rawArgs <- map UTF8.decodeArg <$> getArgs
  prg <- getProgName

  let (actions, args, unrecognizedOpts, errors) =
           getOpt' Permute options' rawArgs

  let unknownOptionErrors = foldr handleUnrecognizedOption [] unrecognizedOpts

  unless (null errors && null unknownOptionErrors) $
     err 2 $ concat errors ++ unlines unknownOptionErrors ++
        ("Try " ++ prg ++ " --help for more information.")

  -- thread option data structure through all supplied option actions
  opts <- foldl (>>=) (return defaults) actions
  return (opts{ optInputFiles = args })

convertWithOpts :: Opt -> IO ()
convertWithOpts opts = do
  let args = optInputFiles opts
  let outputFile = optOutputFile opts
  let filters = optFilters opts
  let verbosity = optVerbosity opts

  when (optDumpArgs opts) $
    do UTF8.hPutStrLn stdout outputFile
       mapM_ (UTF8.hPutStrLn stdout) args
       exitSuccess

  epubStylesheet <- case optEpubStylesheet opts of
                         Nothing -> return Nothing
                         Just fp -> Just <$> UTF8.readFile fp

  epubMetadata <- case optEpubMetadata opts of
                         Nothing -> return Nothing
                         Just fp -> Just <$> UTF8.readFile fp

  let csscdn = "https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.6.0/katex.min.css"
  let mathMethod =
        case (optKaTeXJS opts, optKaTeXStylesheet opts) of
            (Nothing, _) -> optHTMLMathMethod opts
            (Just js, ss) -> KaTeX js (fromMaybe csscdn ss)


  -- --bibliography implies -F pandoc-citeproc for backwards compatibility:
  let needsCiteproc = isJust (lookup "bibliography" (optMetadata opts)) &&
                      optCiteMethod opts `notElem` [Natbib, Biblatex] &&
                      "pandoc-citeproc" `notElem` map takeBaseName filters
  let filters' = if needsCiteproc then "pandoc-citeproc" : filters
                                  else filters

  let sources = case args of
                     []  -> ["-"]
                     xs | optIgnoreArgs opts -> ["-"]
                        | otherwise  -> xs

  datadir <- case optDataDir opts of
                  Nothing   -> E.catch
                                 (Just <$> getAppUserDataDirectory "pandoc")
                                 (\e -> let _ = (e :: E.SomeException)
                                        in  return Nothing)
                  Just _    -> return $ optDataDir opts

  -- assign reader and writer based on options and filenames
  let readerName = case optReader opts of
                          Nothing -> defaultReaderName
                                      (if any isURI sources
                                          then "html"
                                          else "markdown") sources
                          Just x  -> map toLower x

  let writerName = case optWriter opts of
                          Nothing   -> defaultWriterName outputFile
                          Just x    -> map toLower x
  let format = takeWhile (`notElem` ['+','-'])
                       $ takeFileName writerName  -- in case path to lua script

  let pdfOutput = map toLower (takeExtension outputFile) == ".pdf"

  let laTeXOutput = format `elem` ["latex", "beamer"]
  let conTeXtOutput = format == "context"
  let html5Output = format == "html5" || format == "html"

  -- disabling the custom writer for now
  writer <- if ".lua" `isSuffixOf` format
               -- note:  use non-lowercased version writerName
               then error "custom writers disabled for now"
               else case getWriter writerName of
                         Left e  -> err 9 $
                           if format == "pdf"
                              then e ++
                               "\nTo create a pdf with pandoc, use " ++
                               "the latex or beamer writer and specify\n" ++
                               "an output file with .pdf extension " ++
                               "(pandoc -t latex -o filename.pdf)."
                              else e
                         Right w -> return (w :: Writer PandocIO)

  -- TODO: we have to get the input and the output into the state for
  -- the sake of the text2tags reader.
  reader <-  case getReader readerName of
                Right r  -> return (r :: Reader PandocIO)
                Left e   -> err 7 e'
                  where e' = case readerName of
                                  "pdf" -> e ++
                                     "\nPandoc can convert to PDF, but not from PDF."
                                  "doc" -> e ++
                                     "\nPandoc can convert from DOCX, but not from DOC.\nTry using Word to save your DOC file as DOCX, and convert that with pandoc."
                                  _ -> e

  let standalone = optStandalone opts || not (isTextFormat format) || pdfOutput

  templ <- case optTemplate opts of
                _ | not standalone -> return Nothing
                Nothing -> do
                           deftemp <- getDefaultTemplate datadir format
                           case deftemp of
                                 Left e   -> throwIO e
                                 Right t  -> return (Just t)
                Just tp -> do
                           -- strip off extensions
                           let tp' = case takeExtension tp of
                                          ""   -> tp <.> format
                                          _    -> tp
                           Just <$> E.catch (UTF8.readFile tp')
                             (\e -> if isDoesNotExistError e
                                       then E.catch
                                             (readDataFileUTF8 datadir
                                                ("templates" </> tp'))
                                             (\e' -> let _ = (e' :: E.SomeException)
                                                     in throwIO e')
                                       else throwIO e)

  let addStringAsVariable varname s vars = return $ (varname, s) : vars

  let addContentsAsVariable varname fp vars = do
             s <- UTF8.readFile fp
             return $ (varname, s) : vars

  -- note: this reverses the list constructed in option parsing,
  -- which in turn was reversed from the command-line order,
  -- so we end up with the correct order in the variable list:
  let withList _ [] vars = return vars
      withList f (x:xs) vars = f x vars >>= withList f xs

  variables <- return (optVariables opts)
      >>=
      withList (addContentsAsVariable "include-before")
               (optIncludeBeforeBody opts)
      >>=
      withList (addContentsAsVariable "include-after")
               (optIncludeAfterBody opts)
      >>=
      withList (addContentsAsVariable "header-includes")
               (optIncludeInHeader opts)
      >>=
      withList (addStringAsVariable "css") (optCss opts)
      >>=
      maybe return (addStringAsVariable "title-prefix") (optTitlePrefix opts)
      >>=
      maybe return (addStringAsVariable "epub-cover-image")
                   (optEpubCoverImage opts)
      >>=
      (\vars -> case mathMethod of
                     LaTeXMathML Nothing -> do
                        s <- readDataFileUTF8 datadir "LaTeXMathML.js"
                        return $ ("mathml-script", s) : vars
                     _ -> return vars)
      >>=
      (\vars ->  if format == "dzslides"
                    then do
                        dztempl <- readDataFileUTF8 datadir
                                     ("dzslides" </> "template.html")
                        let dzline = "<!-- {{{{ dzslides core"
                        let dzcore = unlines
                                   $ dropWhile (not . (dzline `isPrefixOf`))
                                   $ lines dztempl
                        return $ ("dzslides-core", dzcore) : vars
                    else return vars)

  let sourceURL = case sources of
                    []    -> Nothing
                    (x:_) -> case parseURI x of
                                Just u
                                  | uriScheme u `elem` ["http:","https:"] ->
                                      Just $ show u{ uriQuery = "",
                                                     uriFragment = "" }
                                _ -> Nothing

  let readerOpts = def{ readerStandalone = standalone
                      , readerColumns = optColumns opts
                      , readerTabStop = optTabStop opts
                      , readerIndentedCodeClasses = optIndentedCodeClasses opts
                      , readerApplyMacros = not laTeXOutput
                      , readerDefaultImageExtension =
                         optDefaultImageExtension opts
                      , readerTrackChanges = optTrackChanges opts
                      }

  highlightStyle <- lookupHighlightStyle $ optHighlightStyle opts

  let writerOptions = def { writerTemplate         = templ,
                            writerVariables        = variables,
                            writerTabStop          = optTabStop opts,
                            writerTableOfContents  = optTableOfContents opts,
                            writerHTMLMathMethod   = mathMethod,
                            writerIncremental      = optIncremental opts,
                            writerCiteMethod       = optCiteMethod opts,
                            writerNumberSections   = optNumberSections opts,
                            writerNumberOffset     = optNumberOffset opts,
                            writerSectionDivs      = optSectionDivs opts,
                            writerReferenceLinks   = optReferenceLinks opts,
                            writerReferenceLocation = optReferenceLocation opts,
                            writerDpi              = optDpi opts,
                            writerWrapText         = optWrapText opts,
                            writerColumns          = optColumns opts,
                            writerEmailObfuscation = optEmailObfuscation opts,
                            writerIdentifierPrefix = optIdentifierPrefix opts,
                            writerSourceURL        = sourceURL,
                            writerUserDataDir      = datadir,
                            writerHtmlQTags        = optHtmlQTags opts,
                            writerTopLevelDivision = optTopLevelDivision opts,
                            writerListings         = optListings opts,
                            writerSlideLevel       = optSlideLevel opts,
                            writerHighlightStyle   = highlightStyle,
                            writerSetextHeaders    = optSetextHeaders opts,
                            writerEpubMetadata     = epubMetadata,
                            writerEpubStylesheet   = epubStylesheet,
                            writerEpubFonts        = optEpubFonts opts,
                            writerEpubChapterLevel = optEpubChapterLevel opts,
                            writerTOCDepth         = optTOCDepth opts,
                            writerReferenceDoc     = optReferenceDoc opts,
                            writerLaTeXArgs        = optLaTeXEngineArgs opts
                          }


#ifdef _WINDOWS
  let istty = True
#else
  istty <- queryTerminal stdOutput
#endif
  when (istty && not (isTextFormat format) && outputFile == "-") $
    err 5 $ "Cannot write " ++ format ++ " output to stdout.\n" ++
            "Specify an output file using the -o option."


  let transforms = case optBaseHeaderLevel opts of
                        x | x > 1 -> [headerShift (x - 1)]
                          | otherwise -> []

  let convertTabs = tabFilter (if optPreserveTabs opts || readerName == "t2t"
                                 then 0
                                 else optTabStop opts)

      readSources :: MonadIO m => [FilePath] -> m String
      readSources srcs = convertTabs . intercalate "\n" <$>
                            mapM readSource srcs

  let runIO' :: PandocIO a -> IO a
      runIO' f = do
        (res, reports) <- runIOorExplode $ do
                             setVerbosity verbosity
                             x <- f
                             rs <- getLog
                             return (x, rs)
        case optLogFile opts of
             Nothing -> return ()
             Just logfile -> B.writeFile logfile (encodeLogMessages reports)
        let isWarning msg = messageVerbosity msg == WARNING
        when (optFailIfWarnings opts && any isWarning reports) $
            err 3 "Failing because there were warnings."
        return res

  let sourceToDoc :: [FilePath] -> PandocIO (Pandoc, MediaBag)
      sourceToDoc sources' =
         case reader of
              StringReader r
                | optFileScope opts || readerName == "json" -> do
                    pairs <- mapM
                      (readSource >=> withMediaBag . r readerOpts) sources
                    return (mconcat (map fst pairs), mconcat (map snd pairs))
                | otherwise ->
                     readSources sources' >>= withMediaBag . r readerOpts
              ByteStringReader r -> do
                pairs <- mapM (readFile' >=>
                                 withMediaBag . r readerOpts) sources
                return (mconcat (map fst pairs), mconcat (map snd pairs))

  runIO' $ do
    (doc, media) <- sourceToDoc sources
    doc' <- (maybe return (extractMedia media) (optExtractMedia opts) >=>
              return . flip (foldr addMetadata) (optMetadata opts) >=>
              applyTransforms transforms >=>
              applyFilters datadir filters' [format]) doc

    case writer of
      -- StringWriter f -> f writerOptions doc' >>= writerFn outputFile
      ByteStringWriter f -> f writerOptions doc' >>= writeFnBinary outputFile
      StringWriter f
        | pdfOutput -> do
                -- make sure writer is latex or beamer or context or html5
                unless (laTeXOutput || conTeXtOutput || html5Output) $
                  err 47 $ "cannot produce pdf output with " ++ format ++
                           " writer"

                let pdfprog = case () of
                                _ | conTeXtOutput -> "context"
                                _ | html5Output   -> "wkhtmltopdf"
                                _                 -> optLaTeXEngine opts
                -- check for pdf creating program
                mbPdfProg <- liftIO $ findExecutable pdfprog
                when (isNothing mbPdfProg) $
                     err 41 $ pdfprog ++ " not found. " ++
                       pdfprog ++ " is needed for pdf output."

                res <- makePDF pdfprog f writerOptions verbosity media doc'
                case res of
                     Right pdf -> writeFnBinary outputFile pdf
                     Left err' -> liftIO $ do
                       B.hPutStr stderr err'
                       B.hPut stderr $ B.pack [10]
                       err 43 "Error producing PDF"
        | otherwise -> do
                let htmlFormat = format `elem`
                      ["html","html4","html5","s5","slidy","slideous","dzslides","revealjs"]
                    selfcontain = if optSelfContained opts && htmlFormat
                                  then makeSelfContained writerOptions media
                                  else return
                    handleEntities = if htmlFormat && optAscii opts
                                     then toEntities
                                     else id
                output <- f writerOptions doc'
                selfcontain (output ++ ['\n' | not standalone]) >>=
                    writerFn outputFile . handleEntities

type Transform = Pandoc -> Pandoc

isTextFormat :: String -> Bool
isTextFormat s = s `notElem` ["odt","docx","epub","epub3"]

externalFilter :: MonadIO m => FilePath -> [String] -> Pandoc -> m Pandoc
externalFilter f args' d = liftIO $ do
  exists <- doesFileExist f
  isExecutable <- if exists
                     then executable <$> getPermissions f
                     else return True
  let (f', args'') = if exists
                        then case map toLower (takeExtension f) of
                                  _ | isExecutable -> ("." </> f, args')
                                  ".py"  -> ("python", f:args')
                                  ".hs"  -> ("runhaskell", f:args')
                                  ".pl"  -> ("perl", f:args')
                                  ".rb"  -> ("ruby", f:args')
                                  ".php" -> ("php", f:args')
                                  ".js"  -> ("node", f:args')
                                  _      -> (f, args')
                        else (f, args')
  unless (exists && isExecutable) $ do
    mbExe <- findExecutable f'
    when (isNothing mbExe) $
      err 83 $ "Error running filter " ++ f ++  ":\n" ++
               "Could not find executable '" ++ f' ++ "'."
  env <- getEnvironment
  let env' = Just $ ("PANDOC_VERSION", pandocVersion) : env
  (exitcode, outbs) <- E.handle filterException $
                              pipeProcess env' f' args'' $ encode d
  case exitcode of
       ExitSuccess    -> return $ either error id $ eitherDecode' outbs
       ExitFailure ec -> err 83 $ "Error running filter " ++ f ++ "\n" ++
                                  "Filter returned error status " ++ show ec
 where filterException :: E.SomeException -> IO a
       filterException e = err 83 $ "Error running filter " ++ f ++ "\n" ++
                                       show e

-- | Data structure for command line options.
data Opt = Opt
    { optTabStop           :: Int     -- ^ Number of spaces per tab
    , optPreserveTabs      :: Bool    -- ^ Preserve tabs instead of converting to spaces
    , optStandalone        :: Bool    -- ^ Include header, footer
    , optReader            :: Maybe String  -- ^ Reader format
    , optWriter            :: Maybe String  -- ^ Writer format
    , optTableOfContents   :: Bool    -- ^ Include table of contents
    , optBaseHeaderLevel   :: Int     -- ^ Base header level
    , optTemplate          :: Maybe FilePath  -- ^ Custom template
    , optVariables         :: [(String,String)] -- ^ Template variables to set
    , optMetadata          :: [(String, String)] -- ^ Metadata fields to set
    , optOutputFile        :: FilePath  -- ^ Name of output file
    , optInputFiles        :: [FilePath] -- ^ Names of input files
    , optNumberSections    :: Bool    -- ^ Number sections in LaTeX
    , optNumberOffset      :: [Int]   -- ^ Starting number for sections
    , optSectionDivs       :: Bool    -- ^ Put sections in div tags in HTML
    , optIncremental       :: Bool    -- ^ Use incremental lists in Slidy/Slideous/S5
    , optSelfContained     :: Bool    -- ^ Make HTML accessible offline
    , optHtmlQTags         :: Bool    -- ^ Use <q> tags in HTML
    , optHighlightStyle    :: Maybe String -- ^ Style to use for highlighted code
    , optTopLevelDivision  :: TopLevelDivision -- ^ Type of the top-level divisions
    , optHTMLMathMethod    :: HTMLMathMethod -- ^ Method to print HTML math
    , optReferenceDoc      :: Maybe FilePath -- ^ Path of reference doc
    , optEpubStylesheet    :: Maybe FilePath   -- ^ EPUB stylesheet
    , optEpubMetadata      :: Maybe FilePath   -- ^ EPUB metadata
    , optEpubFonts         :: [FilePath] -- ^ EPUB fonts to embed
    , optEpubChapterLevel  :: Int     -- ^ Header level at which to split chapters
    , optEpubCoverImage    :: Maybe FilePath -- ^ Cover image for epub
    , optTOCDepth          :: Int     -- ^ Number of levels to include in TOC
    , optDumpArgs          :: Bool    -- ^ Output command-line arguments
    , optIgnoreArgs        :: Bool    -- ^ Ignore command-line arguments
    , optVerbosity         :: Verbosity  -- ^ Verbosity of diagnostic output
    , optLogFile           :: Maybe FilePath -- ^ File to write JSON log output
    , optFailIfWarnings    :: Bool    -- ^ Fail on warnings
    , optReferenceLinks    :: Bool    -- ^ Use reference links in writing markdown, rst
    , optReferenceLocation :: ReferenceLocation -- ^ location for footnotes and link references in markdown output
    , optDpi               :: Int     -- ^ Dpi
    , optWrapText          :: WrapOption  -- ^ Options for wrapping text
    , optColumns           :: Int     -- ^ Line length in characters
    , optFilters           :: [FilePath] -- ^ Filters to apply
    , optEmailObfuscation  :: ObfuscationMethod
    , optIdentifierPrefix  :: String
    , optIndentedCodeClasses :: [String] -- ^ Default classes for indented code blocks
    , optDataDir           :: Maybe FilePath
    , optCiteMethod        :: CiteMethod -- ^ Method to output cites
    , optListings          :: Bool       -- ^ Use listings package for code blocks
    , optLaTeXEngine       :: String     -- ^ Program to use for latex -> pdf
    , optLaTeXEngineArgs   :: [String]   -- ^ Flags to pass to the latex-engine
    , optSlideLevel        :: Maybe Int  -- ^ Header level that creates slides
    , optSetextHeaders     :: Bool       -- ^ Use atx headers for markdown level 1-2
    , optAscii             :: Bool       -- ^ Use ascii characters only in html
    , optDefaultImageExtension :: String -- ^ Default image extension
    , optExtractMedia      :: Maybe FilePath -- ^ Path to extract embedded media
    , optTrackChanges      :: TrackChanges -- ^ Accept or reject MS Word track-changes.
    , optFileScope        :: Bool         -- ^ Parse input files before combining
    , optKaTeXStylesheet   :: Maybe String     -- ^ Path to stylesheet for KaTeX
    , optKaTeXJS           :: Maybe String     -- ^ Path to js file for KaTeX
    , optTitlePrefix       :: Maybe String     -- ^ Prefix for title
    , optCss               :: [FilePath]       -- ^ CSS files to link to
    , optIncludeBeforeBody :: [FilePath]       -- ^ Files to include before
    , optIncludeAfterBody  :: [FilePath]       -- ^ Files to include after body
    , optIncludeInHeader   :: [FilePath]       -- ^ Files to include in header
    }

-- | Defaults for command-line options.
defaultOpts :: Opt
defaultOpts = Opt
    { optTabStop               = 4
    , optPreserveTabs          = False
    , optStandalone            = False
    , optReader                = Nothing
    , optWriter                = Nothing
    , optTableOfContents       = False
    , optBaseHeaderLevel       = 1
    , optTemplate              = Nothing
    , optVariables             = []
    , optMetadata              = []
    , optOutputFile            = "-"    -- "-" means stdout
    , optInputFiles            = []
    , optNumberSections        = False
    , optNumberOffset          = [0,0,0,0,0,0]
    , optSectionDivs           = False
    , optIncremental           = False
    , optSelfContained         = False
    , optHtmlQTags             = False
    , optHighlightStyle        = Just "pygments"
    , optTopLevelDivision      = TopLevelDefault
    , optHTMLMathMethod        = PlainMath
    , optReferenceDoc          = Nothing
    , optEpubStylesheet        = Nothing
    , optEpubMetadata          = Nothing
    , optEpubFonts             = []
    , optEpubChapterLevel      = 1
    , optEpubCoverImage        = Nothing
    , optTOCDepth              = 3
    , optDumpArgs              = False
    , optIgnoreArgs            = False
    , optVerbosity             = WARNING
    , optLogFile               = Nothing
    , optFailIfWarnings        = False
    , optReferenceLinks        = False
    , optReferenceLocation     = EndOfDocument
    , optDpi                   = 96
    , optWrapText              = WrapAuto
    , optColumns               = 72
    , optFilters               = []
    , optEmailObfuscation      = NoObfuscation
    , optIdentifierPrefix      = ""
    , optIndentedCodeClasses   = []
    , optDataDir               = Nothing
    , optCiteMethod            = Citeproc
    , optListings              = False
    , optLaTeXEngine           = "pdflatex"
    , optLaTeXEngineArgs       = []
    , optSlideLevel            = Nothing
    , optSetextHeaders         = True
    , optAscii                 = False
    , optDefaultImageExtension = ""
    , optExtractMedia          = Nothing
    , optTrackChanges          = AcceptChanges
    , optFileScope             = False
    , optKaTeXStylesheet       = Nothing
    , optKaTeXJS               = Nothing
    , optTitlePrefix           = Nothing
    , optCss                   = []
    , optIncludeBeforeBody     = []
    , optIncludeAfterBody      = []
    , optIncludeInHeader       = []
    }

addMetadata :: (String, String) -> Pandoc -> Pandoc
addMetadata (k, v) (Pandoc meta bs) = Pandoc meta' bs
  where meta' = case lookupMeta k meta of
                      Nothing -> setMeta k v' meta
                      Just (MetaList xs) ->
                                 setMeta k (MetaList (xs ++ [v'])) meta
                      Just x  -> setMeta k (MetaList [x, v']) meta
        v' = readMetaValue v

readMetaValue :: String -> MetaValue
readMetaValue s = case decode (UTF8.fromString s) of
                       Just (Yaml.String t) -> MetaString $ T.unpack t
                       Just (Yaml.Bool b)   -> MetaBool b
                       _                    -> MetaString s

-- Determine default reader based on source file extensions
defaultReaderName :: String -> [FilePath] -> String
defaultReaderName fallback [] = fallback
defaultReaderName fallback (x:xs) =
  case takeExtension (map toLower x) of
    ".xhtml"    -> "html"
    ".html"     -> "html"
    ".htm"      -> "html"
    ".md"       -> "markdown"
    ".markdown" -> "markdown"
    ".tex"      -> "latex"
    ".latex"    -> "latex"
    ".ltx"      -> "latex"
    ".rst"      -> "rst"
    ".org"      -> "org"
    ".lhs"      -> "markdown+lhs"
    ".db"       -> "docbook"
    ".opml"     -> "opml"
    ".wiki"     -> "mediawiki"
    ".dokuwiki" -> "dokuwiki"
    ".textile"  -> "textile"
    ".native"   -> "native"
    ".json"     -> "json"
    ".docx"     -> "docx"
    ".t2t"      -> "t2t"
    ".epub"     -> "epub"
    ".odt"      -> "odt"
    ".pdf"      -> "pdf"  -- so we get an "unknown reader" error
    ".doc"      -> "doc"  -- so we get an "unknown reader" error
    _           -> defaultReaderName fallback xs

-- Determine default writer based on output file extension
defaultWriterName :: FilePath -> String
defaultWriterName "-" = "html" -- no output file
defaultWriterName x =
  case takeExtension (map toLower x) of
    ""          -> "markdown" -- empty extension
    ".tex"      -> "latex"
    ".latex"    -> "latex"
    ".ltx"      -> "latex"
    ".context"  -> "context"
    ".ctx"      -> "context"
    ".rtf"      -> "rtf"
    ".rst"      -> "rst"
    ".s5"       -> "s5"
    ".native"   -> "native"
    ".json"     -> "json"
    ".txt"      -> "markdown"
    ".text"     -> "markdown"
    ".md"       -> "markdown"
    ".markdown" -> "markdown"
    ".textile"  -> "textile"
    ".lhs"      -> "markdown+lhs"
    ".texi"     -> "texinfo"
    ".texinfo"  -> "texinfo"
    ".db"       -> "docbook"
    ".odt"      -> "odt"
    ".docx"     -> "docx"
    ".epub"     -> "epub"
    ".org"      -> "org"
    ".asciidoc" -> "asciidoc"
    ".adoc"     -> "asciidoc"
    ".pdf"      -> "latex"
    ".fb2"      -> "fb2"
    ".opml"     -> "opml"
    ".icml"     -> "icml"
    ".tei.xml"  -> "tei"
    ".tei"      -> "tei"
    ['.',y] | y `elem` ['1'..'9'] -> "man"
    _           -> "html"

-- Transformations of a Pandoc document post-parsing:

extractMedia :: MonadIO m => MediaBag -> FilePath -> Pandoc -> m Pandoc
extractMedia media dir d =
  case [fp | (fp, _, _) <- mediaDirectory media] of
        []  -> return d
        fps -> do
          extractMediaBag True dir media
          return $ walk (adjustImagePath dir fps) d

adjustImagePath :: FilePath -> [FilePath] -> Inline -> Inline
adjustImagePath dir paths (Image attr lab (src, tit))
   | src `elem` paths = Image attr lab (dir ++ "/" ++ src, tit)
adjustImagePath _ _ x = x

applyTransforms :: Monad m => [Transform] -> Pandoc -> m Pandoc
applyTransforms transforms d = return $ foldr ($) d transforms

  -- First we check to see if a filter is found.  If not, and if it's
  -- not an absolute path, we check to see whether it's in `userdir/filters`.
  -- If not, we leave it unchanged.
expandFilterPath :: MonadIO m => Maybe FilePath -> FilePath -> m FilePath
expandFilterPath mbDatadir fp = liftIO $ do
  fpExists <- doesFileExist fp
  if fpExists
     then return fp
     else case mbDatadir of
               Just datadir | isRelative fp -> do
                 let filterPath = (datadir </> "filters" </> fp)
                 filterPathExists <- doesFileExist filterPath
                 if filterPathExists
                    then return filterPath
                    else return fp
               _ -> return fp

applyFilters :: MonadIO m
             => Maybe FilePath -> [FilePath] -> [String] -> Pandoc -> m Pandoc
applyFilters mbDatadir filters args d = do
  expandedFilters <- mapM (expandFilterPath mbDatadir) filters
  foldrM ($) d $ map (flip externalFilter args) expandedFilters

readSource :: MonadIO m => FilePath -> m String
readSource "-" = liftIO UTF8.getContents
readSource src = case parseURI src of
                      Just u | uriScheme u `elem` ["http:","https:"] ->
                                 readURI src
                             | uriScheme u == "file:" ->
                                 liftIO $ UTF8.readFile (uriPath u)
                      _       -> liftIO $ UTF8.readFile src

readURI :: MonadIO m => FilePath -> m String
readURI src = do
  res <- liftIO $ openURL src
  case res of
       Left e        -> liftIO $ throwIO e
       Right (bs,_)  -> return $ UTF8.toString bs

readFile' :: MonadIO m => FilePath -> m B.ByteString
readFile' "-" = liftIO $ B.getContents
readFile' f   = liftIO $ B.readFile f

writeFnBinary :: MonadIO m => FilePath -> B.ByteString -> m ()
writeFnBinary "-" = liftIO . B.putStr
writeFnBinary f   = liftIO . B.writeFile (UTF8.encodePath f)

writerFn :: MonadIO m => FilePath -> String -> m ()
writerFn "-" = liftIO . UTF8.putStr
writerFn f   = liftIO . UTF8.writeFile f

lookupHighlightStyle :: Maybe String -> IO (Maybe Style)
lookupHighlightStyle Nothing = return Nothing
lookupHighlightStyle (Just s) =
  case lookup (map toLower s) highlightingStyles of
       Just sty -> return (Just sty)
       Nothing  -> err 68 $ "Unknown highlight-style " ++ s

-- | A list of functions, each transforming the options data structure
--   in response to a command-line option.
options :: [OptDescr (Opt -> IO Opt)]
options =
    [ Option "fr" ["from","read"]
                 (ReqArg
                  (\arg opt -> return opt { optReader = Just arg })
                  "FORMAT")
                 ""

    , Option "tw" ["to","write"]
                 (ReqArg
                  (\arg opt -> return opt { optWriter = Just arg })
                  "FORMAT")
                 ""

    , Option "o" ["output"]
                 (ReqArg
                  (\arg opt -> return opt { optOutputFile = arg })
                  "FILENAME")
                 "" -- "Name of output file"

    , Option "" ["data-dir"]
                 (ReqArg
                  (\arg opt -> return opt { optDataDir = Just arg })
                 "DIRECTORY") -- "Directory containing pandoc data files."
                ""

    , Option "" ["base-header-level"]
                 (ReqArg
                  (\arg opt ->
                      case safeRead arg of
                           Just t | t > 0 && t < 6 -> do
                               return opt{ optBaseHeaderLevel = t }
                           _              -> err 19
                                       "base-header-level must be 1-5")
                  "NUMBER")
                 "" -- "Headers base level"

     , Option "" ["indented-code-classes"]
                  (ReqArg
                   (\arg opt -> return opt { optIndentedCodeClasses = words $
                                             map (\c -> if c == ',' then ' ' else c) arg })
                   "STRING")
                  "" -- "Classes (whitespace- or comma-separated) to use for indented code-blocks"

    , Option "F" ["filter"]
                 (ReqArg
                  (\arg opt -> return opt { optFilters = arg : optFilters opt })
                  "PROGRAM")
                 "" -- "External JSON filter"

    , Option "p" ["preserve-tabs"]
                 (NoArg
                  (\opt -> return opt { optPreserveTabs = True }))
                 "" -- "Preserve tabs instead of converting to spaces"

    , Option "" ["tab-stop"]
                 (ReqArg
                  (\arg opt ->
                      case safeRead arg of
                           Just t | t > 0 -> return opt { optTabStop = t }
                           _              -> err 31
                                          "tab-stop must be a number greater than 0")
                  "NUMBER")
                 "" -- "Tab stop (default 4)"

    , Option "" ["track-changes"]
                 (ReqArg
                  (\arg opt -> do
                     action <- case arg of
                            "accept" -> return AcceptChanges
                            "reject" -> return RejectChanges
                            "all"    -> return AllChanges
                            _        -> err 6
                               ("Unknown option for track-changes: " ++ arg)
                     return opt { optTrackChanges = action })
                  "accept|reject|all")
                 "" -- "Accepting or reject MS Word track-changes.""

    , Option "" ["file-scope"]
                 (NoArg
                  (\opt -> return opt { optFileScope = True }))
                 "" -- "Parse input files before combining"

    , Option "" ["extract-media"]
                 (ReqArg
                  (\arg opt ->
                    return opt { optExtractMedia = Just arg })
                  "PATH")
                 "" -- "Directory to which to extract embedded media"

    , Option "s" ["standalone"]
                 (NoArg
                  (\opt -> return opt { optStandalone = True }))
                 "" -- "Include needed header and footer on output"

    , Option "" ["template"]
                 (ReqArg
                  (\arg opt ->
                     return opt{ optTemplate = Just arg,
                                 optStandalone = True })
                  "FILENAME")
                 "" -- "Use custom template"

    , Option "M" ["metadata"]
                 (ReqArg
                  (\arg opt -> do
                     let (key, val) = splitField arg
                     return opt{ optMetadata = (key, val) : optMetadata opt })
                  "KEY[:VALUE]")
                 ""

    , Option "V" ["variable"]
                 (ReqArg
                  (\arg opt -> do
                     let (key, val) = splitField arg
                     return opt{ optVariables = (key, val) : optVariables opt })
                  "KEY[:VALUE]")
                 ""

    , Option "D" ["print-default-template"]
                 (ReqArg
                  (\arg _ -> do
                     templ <- getDefaultTemplate Nothing arg
                     case templ of
                          Right t -> UTF8.hPutStr stdout t
                          Left e  -> error $ show e
                     exitSuccess)
                  "FORMAT")
                 "" -- "Print default template for FORMAT"

    , Option "" ["print-default-data-file"]
                 (ReqArg
                  (\arg _ -> do
                     readDataFile Nothing arg >>= BS.hPutStr stdout
                     exitSuccess)
                  "FILE")
                  "" -- "Print default data file"

    , Option "" ["dpi"]
                 (ReqArg
                  (\arg opt ->
                    case safeRead arg of
                         Just t | t > 0 -> return opt { optDpi = t }
                         _              -> err 31
                                        "dpi must be a number greater than 0")
                  "NUMBER")
                 "" -- "Dpi (default 96)"

    , Option "" ["wrap"]
                 (ReqArg
                  (\arg opt ->
                    case safeRead ("Wrap" ++ uppercaseFirstLetter arg) of
                          Just o   -> return opt { optWrapText = o }
                          Nothing  -> err 77 "--wrap must be auto, none, or preserve")
                 "auto|none|preserve")
                 "" -- "Option for wrapping text in output"

    , Option "" ["columns"]
                 (ReqArg
                  (\arg opt ->
                      case safeRead arg of
                           Just t | t > 0 -> return opt { optColumns = t }
                           _              -> err 33
                                   "columns must be a number greater than 0")
                 "NUMBER")
                 "" -- "Length of line in characters"

    , Option "" ["toc", "table-of-contents"]
                (NoArg
                 (\opt -> return opt { optTableOfContents = True }))
               "" -- "Include table of contents"

    , Option "" ["toc-depth"]
                 (ReqArg
                  (\arg opt ->
                      case safeRead arg of
                           Just t | t >= 1 && t <= 6 ->
                                    return opt { optTOCDepth = t }
                           _      -> err 57
                                    "TOC level must be a number between 1 and 6")
                 "NUMBER")
                 "" -- "Number of levels to include in TOC"

    , Option "" ["no-highlight"]
                (NoArg
                 (\opt -> return opt { optHighlightStyle = Nothing }))
                 "" -- "Don't highlight source code"

    , Option "" ["highlight-style"]
                (ReqArg
                 (\arg opt -> return opt{ optHighlightStyle = Just arg })
                 "STYLE")
                 "" -- "Style for highlighted code"

    , Option "H" ["include-in-header"]
                 (ReqArg
                  (\arg opt -> return opt{ optIncludeInHeader =
                                              arg : optIncludeInHeader opt,
                                            optStandalone = True })
                  "FILENAME")
                 "" -- "File to include at end of header (implies -s)"

    , Option "B" ["include-before-body"]
                 (ReqArg
                  (\arg opt -> return opt{ optIncludeBeforeBody =
                                              arg : optIncludeBeforeBody opt,
                                           optStandalone = True })
                  "FILENAME")
                 "" -- "File to include before document body"

    , Option "A" ["include-after-body"]
                 (ReqArg
                  (\arg opt -> return opt{ optIncludeAfterBody =
                                              arg : optIncludeAfterBody opt,
                                           optStandalone = True })
                  "FILENAME")
                 "" -- "File to include after document body"

    , Option "" ["self-contained"]
                 (NoArg
                  (\opt -> return opt { optSelfContained = True,
                                        optStandalone = True }))
                 "" -- "Make slide shows include all the needed js and css"

    , Option "" ["html-q-tags"]
                 (NoArg
                  (\opt ->
                     return opt { optHtmlQTags = True }))
                 "" -- "Use <q> tags for quotes in HTML"

    , Option "" ["ascii"]
                 (NoArg
                  (\opt -> return opt { optAscii = True }))
                 ""  -- "Use ascii characters only in HTML output"

    , Option "" ["reference-links"]
                 (NoArg
                  (\opt -> return opt { optReferenceLinks = True } ))
                 "" -- "Use reference links in parsing HTML"

    , Option "" ["reference-location"]
                 (ReqArg
                  (\arg opt -> do
                     action <- case arg of
                            "block"    -> return EndOfBlock
                            "section"  -> return EndOfSection
                            "document" -> return EndOfDocument
                            _        -> err 6
                               ("Unknown option for reference-location: " ++ arg)
                     return opt { optReferenceLocation = action })
                  "block|section|document")
                 "" -- "Accepting or reject MS Word track-changes.""

    , Option "" ["atx-headers"]
                 (NoArg
                  (\opt -> return opt { optSetextHeaders = False } ))
                 "" -- "Use atx-style headers for markdown"

    , Option "" ["top-level-division"]
                 (ReqArg
                  (\arg opt -> do
                      let tldName = "TopLevel" ++ uppercaseFirstLetter arg
                      case safeRead tldName of
                        Just tlDiv -> return opt { optTopLevelDivision = tlDiv }
                        _       -> err 76 ("Top-level division must be " ++
                                           "section,  chapter, part, or default"))
                   "section|chapter|part")
                 "" -- "Use top-level division type in LaTeX, ConTeXt, DocBook"

    , Option "N" ["number-sections"]
                 (NoArg
                  (\opt -> return opt { optNumberSections = True }))
                 "" -- "Number sections in LaTeX"

    , Option "" ["number-offset"]
                 (ReqArg
                  (\arg opt ->
                      case safeRead ('[':arg ++ "]") of
                           Just ns -> return opt { optNumberOffset = ns,
                                                   optNumberSections = True }
                           _      -> err 57 "could not parse number-offset")
                 "NUMBERS")
                 "" -- "Starting number for sections, subsections, etc."

    , Option "" ["listings"]
                 (NoArg
                  (\opt -> return opt { optListings = True }))
                 "" -- "Use listings package for LaTeX code blocks"

    , Option "i" ["incremental"]
                 (NoArg
                  (\opt -> return opt { optIncremental = True }))
                 "" -- "Make list items display incrementally in Slidy/Slideous/S5"

    , Option "" ["slide-level"]
                 (ReqArg
                  (\arg opt ->
                      case safeRead arg of
                           Just t | t >= 1 && t <= 6 ->
                                    return opt { optSlideLevel = Just t }
                           _      -> err 39
                                    "slide level must be a number between 1 and 6")
                 "NUMBER")
                 "" -- "Force header level for slides"

    , Option "" ["section-divs"]
                 (NoArg
                  (\opt -> return opt { optSectionDivs = True }))
                 "" -- "Put sections in div tags in HTML"

    , Option "" ["default-image-extension"]
                 (ReqArg
                  (\arg opt -> return opt { optDefaultImageExtension = arg })
                   "extension")
                  "" -- "Default extension for extensionless images"

    , Option "" ["email-obfuscation"]
                 (ReqArg
                  (\arg opt -> do
                     method <- case arg of
                            "references" -> return ReferenceObfuscation
                            "javascript" -> return JavascriptObfuscation
                            "none"       -> return NoObfuscation
                            _            -> err 6
                               ("Unknown obfuscation method: " ++ arg)
                     return opt { optEmailObfuscation = method })
                  "none|javascript|references")
                 "" -- "Method for obfuscating email in HTML"

     , Option "" ["id-prefix"]
                  (ReqArg
                   (\arg opt -> return opt { optIdentifierPrefix = arg })
                   "STRING")
                  "" -- "Prefix to add to automatically generated HTML identifiers"

    , Option "T" ["title-prefix"]
                 (ReqArg
                  (\arg opt -> do
                    let newvars = ("title-prefix", arg) : optVariables opt
                    return opt { optVariables = newvars,
                                 optStandalone = True })
                  "STRING")
                 "" -- "String to prefix to HTML window title"

    , Option "c" ["css"]
                 (ReqArg
                  (\arg opt -> return opt{ optCss = arg : optCss opt })
                  -- add new link to end, so it is included in proper order
                  "URL")
                 "" -- "Link to CSS style sheet"

    , Option "" ["reference-doc"]
                 (ReqArg
                  (\arg opt ->
                    return opt { optReferenceDoc = Just arg })
                  "FILENAME")
                 "" -- "Path of custom reference doc"

    , Option "" ["epub-stylesheet"]
                 (ReqArg
                  (\arg opt -> return opt { optEpubStylesheet = Just arg })
                  "FILENAME")
                 "" -- "Path of epub.css"

    , Option "" ["epub-cover-image"]
                 (ReqArg
                  (\arg opt ->
                     return opt { optVariables =
                                 ("epub-cover-image", arg) : optVariables opt })
                  "FILENAME")
                 "" -- "Path of epub cover image"

    , Option "" ["epub-metadata"]
                 (ReqArg
                  (\arg opt -> return opt { optEpubMetadata = Just arg })
                  "FILENAME")
                 "" -- "Path of epub metadata file"

    , Option "" ["epub-embed-font"]
                 (ReqArg
                  (\arg opt ->
                     return opt{ optEpubFonts = arg : optEpubFonts opt })
                  "FILE")
                 "" -- "Directory of fonts to embed"

    , Option "" ["epub-chapter-level"]
                 (ReqArg
                  (\arg opt ->
                      case safeRead arg of
                           Just t | t >= 1 && t <= 6 ->
                                    return opt { optEpubChapterLevel = t }
                           _      -> err 59
                                    "chapter level must be a number between 1 and 6")
                 "NUMBER")
                 "" -- "Header level at which to split chapters in EPUB"

    , Option "" ["latex-engine"]
                 (ReqArg
                  (\arg opt -> do
                     let b = takeBaseName arg
                     if b `elem` ["pdflatex", "lualatex", "xelatex"]
                        then return opt { optLaTeXEngine = arg }
                        else err 45 "latex-engine must be pdflatex, lualatex, or xelatex.")
                  "PROGRAM")
                 "" -- "Name of latex program to use in generating PDF"

    , Option "" ["latex-engine-opt"]
                 (ReqArg
                  (\arg opt -> do
                      let oldArgs = optLaTeXEngineArgs opt
                      return opt { optLaTeXEngineArgs = arg : oldArgs })
                  "STRING")
                 "" -- "Flags to pass to the LaTeX engine, all instances of this option are accumulated and used"

    , Option "" ["bibliography"]
                 (ReqArg
                  (\arg opt -> return opt{ optMetadata =
                                 ("bibliography", arg) : optMetadata opt })
                   "FILE")
                 ""

     , Option "" ["csl"]
                 (ReqArg
                  (\arg opt ->
                     return opt{ optMetadata =
                                   ("csl", arg) : optMetadata opt })
                   "FILE")
                 ""

     , Option "" ["citation-abbreviations"]
                 (ReqArg
                  (\arg opt ->
                     return opt{ optMetadata =
                              ("citation-abbreviations", arg): optMetadata opt })
                   "FILE")
                 ""

    , Option "" ["natbib"]
                 (NoArg
                  (\opt -> return opt { optCiteMethod = Natbib }))
                 "" -- "Use natbib cite commands in LaTeX output"

    , Option "" ["biblatex"]
                 (NoArg
                  (\opt -> return opt { optCiteMethod = Biblatex }))
                 "" -- "Use biblatex cite commands in LaTeX output"

    , Option "m" ["latexmathml", "asciimathml"]
                 (OptArg
                  (\arg opt ->
                      return opt { optHTMLMathMethod = LaTeXMathML arg })
                  "URL")
                 "" -- "Use LaTeXMathML script in html output"

    , Option "" ["mathml"]
                 (NoArg
                  (\opt ->
                      return opt { optHTMLMathMethod = MathML }))
                 "" -- "Use mathml for HTML math"

    , Option "" ["mimetex"]
                 (OptArg
                  (\arg opt -> do
                      let url' = case arg of
                                      Just u   -> u ++ "?"
                                      Nothing  -> "/cgi-bin/mimetex.cgi?"
                      return opt { optHTMLMathMethod = WebTeX url' })
                  "URL")
                 "" -- "Use mimetex for HTML math"

    , Option "" ["webtex"]
                 (OptArg
                  (\arg opt -> do
                      let url' = fromMaybe "https://latex.codecogs.com/png.latex?" arg
                      return opt { optHTMLMathMethod = WebTeX url' })
                  "URL")
                 "" -- "Use web service for HTML math"

    , Option "" ["jsmath"]
                 (OptArg
                  (\arg opt -> return opt { optHTMLMathMethod = JsMath arg})
                  "URL")
                 "" -- "Use jsMath for HTML math"

    , Option "" ["mathjax"]
                 (OptArg
                  (\arg opt -> do
                      let url' = fromMaybe "https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS_CHTML-full" arg
                      return opt { optHTMLMathMethod = MathJax url'})
                  "URL")
                 "" -- "Use MathJax for HTML math"
    , Option "" ["katex"]
                 (OptArg
                  (\arg opt ->
                      return opt
                        { optKaTeXJS =
                           arg <|> Just "https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.6.0/katex.min.js"})
                  "URL")
                  "" -- Use KaTeX for HTML Math

    , Option "" ["katex-stylesheet"]
                 (ReqArg
                  (\arg opt ->
                      return opt { optKaTeXStylesheet = Just arg })
                 "URL")
                 "" -- Set the KaTeX Stylesheet location

    , Option "" ["gladtex"]
                 (NoArg
                  (\opt -> return opt { optHTMLMathMethod = GladTeX }))
                 "" -- "Use gladtex for HTML math"

    , Option "" ["trace"]
                 (NoArg
                  (\opt -> return opt { optVerbosity = DEBUG }))
                 "" -- "Turn on diagnostic tracing in readers."

    , Option "" ["dump-args"]
                 (NoArg
                  (\opt -> return opt { optDumpArgs = True }))
                 "" -- "Print output filename and arguments to stdout."

    , Option "" ["ignore-args"]
                 (NoArg
                  (\opt -> return opt { optIgnoreArgs = True }))
                 "" -- "Ignore command-line arguments."

    , Option "" ["verbose"]
                 (NoArg
                  (\opt -> return opt { optVerbosity = INFO }))
                 "" -- "Verbose diagnostic output."

    , Option "" ["quiet"]
                 (NoArg
                  (\opt -> return opt { optVerbosity = ERROR }))
                 "" -- "Suppress warnings."

    , Option "" ["fail-if-warnings"]
                 (NoArg
                  (\opt -> return opt { optFailIfWarnings = True }))
                 "" -- "Exit with error status if there were  warnings."

    , Option "" ["log"]
                 (ReqArg
                  (\arg opt -> return opt{ optLogFile = Just arg })
                "FILE")
                "" -- "Log messages in JSON format to this file."

    , Option "" ["bash-completion"]
                 (NoArg
                  (\_ -> do
                     ddir <- getDataDir
                     tpl <- readDataFileUTF8 Nothing "bash_completion.tpl"
                     let optnames (Option shorts longs _ _) =
                           map (\c -> ['-',c]) shorts ++
                           map ("--" ++) longs
                     let allopts = unwords (concatMap optnames options)
                     UTF8.hPutStrLn stdout $ printf tpl allopts
                         (unwords readers'names)
                         (unwords writers'names)
                         (unwords $ map fst highlightingStyles)
                         ddir
                     exitSuccess ))
                 "" -- "Print bash completion script"

    , Option "" ["list-input-formats"]
                 (NoArg
                  (\_ -> do
                     mapM_ (UTF8.hPutStrLn stdout) readers'names
                     exitSuccess ))
                 ""

    , Option "" ["list-output-formats"]
                 (NoArg
                  (\_ -> do
                     mapM_ (UTF8.hPutStrLn stdout) writers'names
                     exitSuccess ))
                 ""

    , Option "" ["list-extensions"]
                 (NoArg
                  (\_ -> do
                     let showExt x = drop 4 (show x) ++
                                       if extensionEnabled x pandocExtensions
                                          then " +"
                                          else " -"
                     mapM_ (UTF8.hPutStrLn stdout . showExt)
                               ([minBound..maxBound] :: [Extension])
                     exitSuccess ))
                 ""

    , Option "" ["list-highlight-languages"]
                 (NoArg
                  (\_ -> do
                     let langs = [ T.unpack (T.toLower (sShortname s))
                                 | s <- M.elems defaultSyntaxMap
                                 , sShortname s `notElem`
                                    [T.pack "Alert", T.pack "Alert_indent"]
                                 ]
                     mapM_ (UTF8.hPutStrLn stdout) langs
                     exitSuccess ))
                 ""

    , Option "" ["list-highlight-styles"]
                 (NoArg
                  (\_ -> do
                     mapM_ (UTF8.hPutStrLn stdout) $
                           map fst highlightingStyles
                     exitSuccess ))
                 ""

    , Option "v" ["version"]
                 (NoArg
                  (\_ -> do
                     prg <- getProgName
                     defaultDatadir <- E.catch
                            (getAppUserDataDirectory "pandoc")
                            (\e -> let _ = (e :: E.SomeException)
                                   in  return "")
                     UTF8.hPutStrLn stdout (prg ++ " " ++ pandocVersion ++
                       compileInfo ++ "\nDefault user data directory: " ++
                       defaultDatadir ++ copyrightMessage)
                     exitSuccess ))
                 "" -- "Print version"

    , Option "h" ["help"]
                 (NoArg
                  (\_ -> do
                     prg <- getProgName
                     UTF8.hPutStr stdout (usageMessage prg options)
                     exitSuccess ))
                 "" -- "Show help"

    ]

-- Returns usage message
usageMessage :: String -> [OptDescr (Opt -> IO Opt)] -> String
usageMessage programName = usageInfo (programName ++ " [OPTIONS] [FILES]")

copyrightMessage :: String
copyrightMessage = intercalate "\n" [
  "",
  "Copyright (C) 2006-2017 John MacFarlane",
  "Web:  http://pandoc.org",
  "This is free software; see the source for copying conditions.",
  "There is no warranty, not even for merchantability or fitness",
  "for a particular purpose." ]

compileInfo :: String
compileInfo =
  "\nCompiled with pandoc-types " ++ VERSION_pandoc_types ++ ", texmath " ++
  VERSION_texmath ++ ", skylighting " ++ VERSION_skylighting

handleUnrecognizedOption :: String -> [String] -> [String]
handleUnrecognizedOption "--smart" =
  (("--smart/-S has been removed.  Use +smart or -smart extension instead.\n" ++
    "For example: pandoc -f markdown+smart -t markdown-smart.") :)
handleUnrecognizedOption "-S" = handleUnrecognizedOption "--smart"
handleUnrecognizedOption "--old-dashes" =
  ("--old-dashes has been removed.  Use +old_dashes extension instead." :)
handleUnrecognizedOption "--no-wrap" =
  ("--no-wrap has been removed.  Use --wrap=none instead." :)
handleUnrecognizedOption "--chapters" =
  ("--chapters has been removed. Use --top-level-division=chapter instead." :)
handleUnrecognizedOption "--reference-docx" =
  ("--reference-docx has been removed. Use --reference-doc instead." :)
handleUnrecognizedOption "--reference-odt" =
  ("--reference-odt has been removed. Use --reference-doc instead." :)
handleUnrecognizedOption "--parse-raw" =
  (("--parse-raw/-R has been removed. Use +raw_html or +raw_tex extension.\n") :)
handleUnrecognizedOption "-R" = handleUnrecognizedOption "--parse-raw"
handleUnrecognizedOption x =
  (("Unknown option " ++ x ++ ".") :)

uppercaseFirstLetter :: String -> String
uppercaseFirstLetter (c:cs) = toUpper c : cs
uppercaseFirstLetter [] = []

readers'names :: [String]
readers'names = sort (map fst (readers :: [(String, Reader PandocIO)]))

writers'names :: [String]
writers'names = sort (map fst (writers :: [(String, Writer PandocIO)]))

splitField :: String -> (String, String)
splitField s =
  case break (`elem` ":=") s of
       (k,_:v) -> (k,v)
       (k,[])  -> (k,"true")