summaryrefslogtreecommitdiff
path: root/src/Text/Pandoc/Writers/HTML.hs
blob: fb7320e927e55d6e5a12ee367db2eb665ac9680c (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
{-# OPTIONS_GHC -fno-warn-deprecations #-}
{-
Copyright (C) 2006-8 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.Writers.HTML 
   Copyright   : Copyright (C) 2006-8 John MacFarlane
   License     : GNU GPL, version 2 or above 

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

Conversion of 'Pandoc' documents to HTML.
-}
module Text.Pandoc.Writers.HTML ( writeHtml , writeHtmlString ) where
import Text.Pandoc.Definition
import Text.Pandoc.LaTeXMathML
import Text.Pandoc.CharacterReferences ( decodeCharacterReferences )
import Text.Pandoc.Shared
import Text.Pandoc.Readers.TeXMath
import Text.Pandoc.Highlighting ( highlightHtml, defaultHighlightingCss )
import Numeric ( showHex )
import Data.Char ( ord, toLower, isAlpha )
import Data.List ( isPrefixOf, intercalate )
import qualified Data.Set as S
import Control.Monad.State
import Text.XHtml.Transitional hiding ( stringToHtml )

data WriterState = WriterState
    { stNotes            :: [Html]       -- ^ List of notes
    , stIds              :: [String]     -- ^ List of header identifiers
    , stMath             :: Bool         -- ^ Math is used in document
    , stCSS              :: S.Set String -- ^ CSS to include in header
    } deriving Show

defaultWriterState :: WriterState
defaultWriterState = WriterState {stNotes= [], stIds = [], 
                                  stMath = False, stCSS = S.empty}

-- Helpers to render HTML with the appropriate function.

render :: (HTML html) => WriterOptions -> html -> String
render opts = if writerWrapText opts then renderHtml else showHtml

renderFragment :: (HTML html) => WriterOptions -> html -> String
renderFragment opts = if writerWrapText opts
                         then renderHtmlFragment
                         else showHtmlFragment

-- | Slightly modified version of Text.XHtml's stringToHtml.
-- Only uses numerical entities for 0xff and greater.
-- Adds &nbsp;.
stringToHtml :: String -> Html
stringToHtml = primHtml . concatMap fixChar
    where
      fixChar '<' = "&lt;"
      fixChar '>' = "&gt;"
      fixChar '&' = "&amp;"
      fixChar '"' = "&quot;"
      fixChar '\160' = "&nbsp;"
      fixChar c | ord c < 0xff = [c]
      fixChar c = "&#" ++ show (ord c) ++ ";"

-- | Convert Pandoc document to Html string.
writeHtmlString :: WriterOptions -> Pandoc -> String
writeHtmlString opts = 
  if writerStandalone opts
     then render opts . writeHtml opts
     else renderFragment opts . writeHtml opts

-- | Convert Pandoc document to Html structure.
writeHtml :: WriterOptions -> Pandoc -> Html
writeHtml opts (Pandoc (Meta tit authors date) blocks) = 
  let titlePrefix = writerTitlePrefix opts
      topTitle    = evalState (inlineListToHtml opts tit) defaultWriterState
      topTitle'   = if null titlePrefix
                       then topTitle
                       else if null tit 
                               then stringToHtml titlePrefix
                               else titlePrefix +++ " - " +++ topTitle
      metadata    = thetitle topTitle' +++ 
                    meta ! [httpequiv "Content-Type", 
                            content "text/html; charset=UTF-8"] +++
                    meta ! [name "generator", content "pandoc"] +++
                    (toHtmlFromList $ 
                    map (\a -> meta ! [name "author", content a]) authors) +++
                    (if null date
                       then noHtml
                       else meta ! [name "date", content date])
      titleHeader = if writerStandalone opts && not (null tit) && 
                    not (writerS5 opts)
                        then h1 ! [theclass "title"] $ topTitle
                        else noHtml
      headerBlocks = filter isHeaderBlock blocks
      ids          = uniqueIdentifiers $ 
                     map (\(Header _ lst) -> lst) headerBlocks
      toc          = if writerTableOfContents opts 
                        then tableOfContents opts headerBlocks ids
                        else noHtml
      (blocks', newstate) = 
                     runState (blockListToHtml opts blocks)
                     (defaultWriterState {stIds = ids})
      cssLines     = stCSS newstate
      css          = if S.null cssLines
                        then noHtml
                        else style ! [thetype "text/css"] $ primHtml $
                             '\n':(unlines $ S.toList cssLines)
      math         = if stMath newstate
                        then case writerHTMLMathMethod opts of
                                   LaTeXMathML Nothing -> 
                                      primHtml latexMathMLScript
                                   LaTeXMathML (Just url) ->
                                      script ! 
                                      [src url, thetype "text/javascript"] $
                                      noHtml
                                   JsMath (Just url) ->
                                      script !
                                      [src url, thetype "text/javascript"] $
                                      noHtml
                                   _ -> noHtml
                        else noHtml
      head'        = header $ metadata +++ math +++ css +++ 
                              primHtml (writerHeader opts)
      notes        = reverse (stNotes newstate)
      before       = primHtml $ writerIncludeBefore opts
      after        = primHtml $ writerIncludeAfter opts
      thebody      = before +++ titleHeader +++ toc +++ blocks' +++
                     footnoteSection notes +++ after
  in  if writerStandalone opts
         then head' +++ body thebody
         else thebody

-- | Construct table of contents from list of header blocks and identifiers.
-- Assumes there are as many identifiers as header blocks.
tableOfContents :: WriterOptions -> [Block] -> [String] -> Html
tableOfContents _ [] _ = noHtml
tableOfContents opts headers ids =
  let opts'        = opts { writerIgnoreNotes = True }
      contentsTree = hierarchicalize headers
      contents     = evalState (mapM (elementToListItem opts') contentsTree) 
                     (defaultWriterState {stIds = ids})
  in  thediv ! [identifier "toc"] $ unordList contents

-- | Converts an Element to a list item for a table of contents,
-- retrieving the appropriate identifier from state.
elementToListItem :: WriterOptions -> Element -> State WriterState Html
elementToListItem _ (Blk _) = return noHtml
elementToListItem opts (Sec headerText subsecs) = do
  st <- get
  let ids = stIds st
  let (id', rest) = if null ids
                      then ("", [])
                      else (head ids, tail ids)
  put $ st {stIds = rest}
  txt <- inlineListToHtml opts headerText
  subHeads <- mapM (elementToListItem opts) subsecs
  let subList = if null subHeads
                   then noHtml
                   else unordList subHeads 
  return $ (anchor ! [href ("#" ++ id'), identifier ("TOC-" ++ id')] $ txt) +++ 
           subList

-- | Convert list of Note blocks to a footnote <div>.
-- Assumes notes are sorted.
footnoteSection :: [Html] -> Html
footnoteSection notes =
  if null notes 
     then noHtml
     else thediv ! [theclass "footnotes"] $ hr +++ (olist << notes)


-- | Parse a mailto link; return Just (name, domain) or Nothing.
parseMailto :: String -> Maybe (String, String)
parseMailto ('m':'a':'i':'l':'t':'o':':':addr) =
  let (name', rest) = span (/='@') addr
      domain = drop 1 rest
  in  Just (name', domain)
parseMailto _ = Nothing 

-- | Obfuscate a "mailto:" link.
obfuscateLink :: WriterOptions -> String -> String -> Html
obfuscateLink opts txt s | writerEmailObfuscation opts == NoObfuscation =
  anchor ! [href s] << txt
obfuscateLink opts txt s =
  let meth = writerEmailObfuscation opts
      s' = map toLower s 
  in  case parseMailto s' of
        (Just (name', domain)) ->
          let domain'  = substitute "." " dot " domain
              at'      = obfuscateChar '@'
              (linkText, altText) = 
                 if txt == drop 7 s' -- autolink
                    then ("'<code>'+e+'</code>'", name' ++ " at " ++ domain')
                    else ("'" ++ txt ++ "'", txt ++ " (" ++ name' ++ " at " ++ 
                          domain' ++ ")")
          in  case meth of
                ReferenceObfuscation ->
                     -- need to use primHtml or &'s are escaped to &amp; in URL
                     primHtml $ "<a href=\"" ++ (obfuscateString s')
                     ++ "\">" ++ (obfuscateString txt) ++ "</a>"
                JavascriptObfuscation ->
                     (script ! [thetype "text/javascript"] $
                     primHtml ("\n<!--\nh='" ++ 
                     obfuscateString domain ++ "';a='" ++ at' ++ "';n='" ++ 
                     obfuscateString name' ++ "';e=n+a+h;\n" ++
                     "document.write('<a h'+'ref'+'=\"ma'+'ilto'+':'+e+'\">'+" ++ 
                     linkText  ++ "+'<\\/'+'a'+'>');\n// -->\n")) +++  
                     noscript (primHtml $ obfuscateString altText)
                _ -> error $ "Unknown obfuscation method: " ++ show meth
        _ -> anchor ! [href s] $ primHtml txt  -- malformed email

-- | Obfuscate character as entity.
obfuscateChar :: Char -> String
obfuscateChar char = 
  let num    = ord char
      numstr = if even num then show num else "x" ++ showHex num ""
  in  "&#" ++ numstr ++ ";"

-- | Obfuscate string using entities.
obfuscateString :: String -> String
obfuscateString = concatMap obfuscateChar . decodeCharacterReferences

-- | True if character is a punctuation character (unicode).
isPunctuation :: Char -> Bool
isPunctuation c =
  let c' = ord c
  in  if c `elem` "!\"'()*,-./:;<>?[\\]`{|}~" || c' >= 0x2000 && c' <= 0x206F ||
         c' >= 0xE000 && c' <= 0xE0FF
         then True
         else False

-- | Add CSS for document header.
addToCSS :: String -> State WriterState ()
addToCSS item = do
  st <- get
  let current = stCSS st
  put $ st {stCSS = S.insert item current}

-- | Convert Pandoc inline list to plain text identifier.
inlineListToIdentifier :: [Inline] -> String
inlineListToIdentifier = dropWhile (not . isAlpha) . inlineListToIdentifier'

inlineListToIdentifier' :: [Inline] -> [Char]
inlineListToIdentifier' [] = ""
inlineListToIdentifier' (x:xs) = 
  xAsText ++ inlineListToIdentifier' xs
  where xAsText = case x of
          Str s          -> filter (\c -> c == '-' || not (isPunctuation c)) $
                            intercalate "-" $ words $ map toLower s
          Emph lst       -> inlineListToIdentifier' lst
          Strikeout lst  -> inlineListToIdentifier' lst
          Superscript lst -> inlineListToIdentifier' lst
          SmallCaps   lst -> inlineListToIdentifier' lst
          Subscript lst  -> inlineListToIdentifier' lst
          Strong lst     -> inlineListToIdentifier' lst
          Quoted _ lst   -> inlineListToIdentifier' lst
          Cite   _ lst   -> inlineListToIdentifier' lst
          Code s         -> s
          Space          -> "-"
          EmDash         -> "-"
          EnDash         -> "-"
          Apostrophe     -> ""
          Ellipses       -> ""
          LineBreak      -> "-"
          Math _ _       -> ""
          TeX _          -> ""
          HtmlInline _   -> ""
          Link lst _     -> inlineListToIdentifier' lst
          Image lst _    -> inlineListToIdentifier' lst
          Note _         -> ""

-- | Return unique identifiers for list of inline lists.
uniqueIdentifiers :: [[Inline]] -> [String]
uniqueIdentifiers ls =
  let addIdentifier (nonuniqueIds, uniqueIds) l =
        let new = inlineListToIdentifier l
            matches = length $ filter (== new) nonuniqueIds
            new' = (if null new then "section" else new) ++ 
                   if matches > 0 then ("-" ++ show matches) else ""
        in  (new:nonuniqueIds, new':uniqueIds)
  in  reverse $ snd $ foldl addIdentifier ([],[]) ls

-- | Convert Pandoc block element to HTML.
blockToHtml :: WriterOptions -> Block -> State WriterState Html
blockToHtml _ Null = return $ noHtml 
blockToHtml opts (Plain lst) = inlineListToHtml opts lst
blockToHtml opts (Para lst) = inlineListToHtml opts lst >>= (return . paragraph)
blockToHtml _ (RawHtml str) = return $ primHtml str
blockToHtml _ (HorizontalRule) = return $ hr
blockToHtml opts (CodeBlock (_,classes,_) rawCode) | "haskell" `elem` classes &&
                                                          writerLiterateHaskell opts =
  let classes' = map (\c -> if c == "haskell" then "literatehaskell" else c) classes
  in  blockToHtml opts $ CodeBlock ("",classes',[]) $ intercalate "\n" $ map ("> " ++) $ lines rawCode
blockToHtml _ (CodeBlock attr@(_,classes,_) rawCode) = do
  case highlightHtml attr rawCode of
         Left _  -> -- change leading newlines into <br /> tags, because some
                    -- browsers ignore leading newlines in pre blocks
                    let (leadingBreaks, rawCode') = span (=='\n') rawCode
                    in  return $ pre ! (if null classes
                                           then []
                                           else [theclass $ unwords classes]) $ thecode <<
                                                (replicate (length leadingBreaks) br +++
                                                [stringToHtml $ rawCode' ++ "\n"])
         Right h -> addToCSS defaultHighlightingCss >> return h
blockToHtml opts (BlockQuote blocks) =
  -- in S5, treat list in blockquote specially
  -- if default is incremental, make it nonincremental; 
  -- otherwise incremental
  if writerS5 opts
     then let inc = not (writerIncremental opts) in
          case blocks of 
             [BulletList lst]  -> blockToHtml (opts {writerIncremental = inc})
                                  (BulletList lst)
             [OrderedList attribs lst] -> 
                                  blockToHtml (opts {writerIncremental = inc})
                                  (OrderedList attribs lst)
             _                 -> blockListToHtml opts blocks >>= 
                                  (return . blockquote)
     else blockListToHtml opts blocks >>= (return . blockquote)
blockToHtml opts (Header level lst) = do 
  contents <- inlineListToHtml opts lst
  st <- get
  let ids = stIds st
  let (id', rest) = if null ids
                      then ("", [])
                      else (head ids, tail ids)
  put $ st {stIds = rest}
  let attribs = if writerStrictMarkdown opts && not (writerTableOfContents opts)
                   then []
                   else [identifier id']
  let contents'  = if writerTableOfContents opts
                      then anchor ! [href ("#TOC-" ++ id')] $ contents
                      else contents
  return $ case level of
              1 -> h1 contents' ! attribs
              2 -> h2 contents' ! attribs
              3 -> h3 contents' ! attribs
              4 -> h4 contents' ! attribs
              5 -> h5 contents' ! attribs
              6 -> h6 contents' ! attribs
              _ -> paragraph contents' ! attribs
blockToHtml opts (BulletList lst) = do
  contents <- mapM (blockListToHtml opts) lst
  let attribs = if writerIncremental opts
                   then [theclass "incremental"]
                   else []
  return $ unordList ! attribs $ contents
blockToHtml opts (OrderedList (startnum, numstyle, _) lst) = do
  contents <- mapM (blockListToHtml opts) lst
  let numstyle' = camelCaseToHyphenated $ show numstyle
  let attribs = (if writerIncremental opts
                   then [theclass "incremental"]
                   else []) ++
                (if startnum /= 1
                   then [start startnum]
                   else []) ++
                (if numstyle /= DefaultStyle
                   then [thestyle $ "list-style-type: " ++ numstyle' ++ ";"]
                   else [])
  return $ ordList ! attribs $ contents
blockToHtml opts (DefinitionList lst) = do
  contents <- mapM (\(term, def) -> do term' <- inlineListToHtml opts term
                                       def' <- blockListToHtml opts def
                                       return $ (term', def')) lst
  let attribs = if writerIncremental opts
                   then [theclass "incremental"]
                   else []
  return $ defList ! attribs $ contents
blockToHtml opts (Table capt aligns widths headers rows') = do
  let alignStrings = map alignmentToString aligns
  captionDoc <- if null capt
                   then return noHtml
                   else inlineListToHtml opts capt >>= return . caption
  colHeads <- colHeadsToHtml opts alignStrings 
                             widths headers
  rows'' <- zipWithM (tableRowToHtml opts alignStrings) (cycle ["odd", "even"]) rows'
  return $ table $ captionDoc +++ colHeads +++ rows''

colHeadsToHtml :: WriterOptions
               -> [[Char]]
               -> [Double]
               -> [[Block]]
               -> State WriterState Html
colHeadsToHtml opts alignStrings widths headers = do
  heads <- sequence $ zipWith3 
           (\alignment columnwidth item -> tableItemToHtml opts th alignment columnwidth item) 
           alignStrings widths headers
  return $ tr ! [theclass "header"] $ toHtmlFromList heads

alignmentToString :: Alignment -> [Char]
alignmentToString alignment = case alignment of
                                 AlignLeft    -> "left"
                                 AlignRight   -> "right"
                                 AlignCenter  -> "center"
                                 AlignDefault -> "left"

tableRowToHtml :: WriterOptions
               -> [[Char]]
               -> String
               -> [[Block]]
               -> State WriterState Html
tableRowToHtml opts aligns rowclass columns =
  (sequence $ zipWith3 (tableItemToHtml opts td) aligns (repeat 0) columns) >>=
  return . (tr ! [theclass rowclass]) . toHtmlFromList

tableItemToHtml :: WriterOptions
                -> (Html -> Html)
                -> [Char]
                -> Double
                -> [Block]
                -> State WriterState Html
tableItemToHtml opts tag' align' width' item = do
  contents <- blockListToHtml opts item
  let attrib = [align align'] ++ 
               if width' /= 0
                  then [thestyle ("width: " ++ (show  (truncate (100 * width') :: Integer)) ++ "%;")]
                  else [] 
  return $ tag' ! attrib $ contents

blockListToHtml :: WriterOptions -> [Block] -> State WriterState Html
blockListToHtml opts lst = 
  mapM (blockToHtml opts) lst >>= return . toHtmlFromList

-- | Convert list of Pandoc inline elements to HTML.
inlineListToHtml :: WriterOptions -> [Inline] -> State WriterState Html
inlineListToHtml opts lst = 
  mapM (inlineToHtml opts) lst >>= return . toHtmlFromList

-- | Convert Pandoc inline element to HTML.
inlineToHtml :: WriterOptions -> Inline -> State WriterState Html
inlineToHtml opts inline =
  case inline of  
    (Str str)        -> return $ stringToHtml str
    (Space)          -> return $ stringToHtml " "
    (LineBreak)      -> return $ br
    (EmDash)         -> return $ primHtmlChar "mdash"
    (EnDash)         -> return $ primHtmlChar "ndash"
    (Ellipses)       -> return $ primHtmlChar "hellip"
    (Apostrophe)     -> return $ primHtmlChar "rsquo"
    (Emph lst)       -> inlineListToHtml opts lst >>= return . emphasize
    (Strong lst)     -> inlineListToHtml opts lst >>= return . strong
    (Code str)       -> return $ thecode << str
    (Strikeout lst)  -> inlineListToHtml opts lst >>=
                        return . (thespan ! [thestyle "text-decoration: line-through;"])
    (SmallCaps lst)   -> inlineListToHtml opts lst >>=
                         return . (thespan ! [thestyle "font-variant: small-caps;"])
    (Superscript lst) -> inlineListToHtml opts lst >>= return . sup
    (Subscript lst)   -> inlineListToHtml opts lst >>= return . sub
    (Quoted quoteType lst) ->
                        let (leftQuote, rightQuote) = case quoteType of
                              SingleQuote -> (primHtmlChar "lsquo", 
                                              primHtmlChar "rsquo")
                              DoubleQuote -> (primHtmlChar "ldquo", 
                                              primHtmlChar "rdquo")
                        in  do contents <- inlineListToHtml opts lst
                               return $ leftQuote +++ contents +++ rightQuote
    (Math t str) -> 
                        modify (\st -> st {stMath = True}) >> 
                        (case writerHTMLMathMethod opts of
                               LaTeXMathML _ -> 
                                  -- putting LaTeXMathML in container with class "LaTeX" prevents
                                  -- non-math elements on the page from being treated as math by
                                  -- the javascript
                                  return $ thespan ! [theclass "LaTeX"] $
                                             if t == InlineMath
                                                 then primHtml ("$" ++ str ++ "$")
                                                 else primHtml ("$$" ++ str ++ "$$")
                               JsMath _ ->
                                  return $ if t == InlineMath
                                              then thespan ! [theclass "math"] $ primHtml str
                                              else thediv ! [theclass "math"]  $ primHtml str
                               MimeTeX url -> 
                                  return $ image ! [src (url ++ "?" ++ str),
                                                    alt str, title str]
                               GladTeX ->
                                  return $ primHtml $ "<EQ>" ++ str ++ "</EQ>"
                               PlainMath -> 
                                  inlineListToHtml opts (readTeXMath str) >>=
                                  return . (thespan ! [theclass "math"])) 
    (TeX str)        -> case writerHTMLMathMethod opts of
                              LaTeXMathML _ -> do modify (\st -> st {stMath = True})
                                                  return $ primHtml str
                              _             -> return noHtml
    (HtmlInline str) -> return $ primHtml str 
    (Link [Code str] (s,_)) | "mailto:" `isPrefixOf` s ->
                        return $ obfuscateLink opts str s
    (Link txt (s,_)) | "mailto:" `isPrefixOf` s -> do
                        linkText <- inlineListToHtml opts txt  
                        return $ obfuscateLink opts (show linkText) s
    (Link txt (s,tit)) -> do
                        linkText <- inlineListToHtml opts txt
                        return $ anchor ! ([href s] ++ 
                                 if null tit then [] else [title tit]) $ 
                                 linkText
    (Image txt (s,tit)) -> do
                        alternate <- inlineListToHtml opts txt
                        let alternate' = renderFragment opts alternate
                        let attributes = [src s] ++
                                         (if null tit 
                                            then [] 
                                            else [title tit]) ++ 
                                         if null txt 
                                            then [] 
                                            else [alt alternate']
                        return $ image ! attributes 
                        -- note:  null title included, as in Markdown.pl 
    (Note contents)          -> do 
                        st <- get
                        let notes = stNotes st
                        let number = (length notes) + 1
                        let ref = show number
                        htmlContents <- blockListToNote opts ref contents 
                        -- push contents onto front of notes
                        put $ st {stNotes = (htmlContents:notes)} 
                        return $ anchor ! [href ("#fn" ++ ref),
                                          theclass "footnoteRef",
                                          identifier ("fnref" ++ ref)] << 
                                          sup << ref
    (Cite _ il)  -> inlineListToHtml opts il

blockListToNote :: WriterOptions -> String -> [Block] -> State WriterState Html
blockListToNote opts ref blocks =
  -- If last block is Para or Plain, include the backlink at the end of
  -- that block. Otherwise, insert a new Plain block with the backlink.
  let backlink = [HtmlInline $ " <a href=\"#fnref" ++ ref ++ 
                 "\" class=\"footnoteBackLink\"" ++
                 " title=\"Jump back to footnote " ++ ref ++ "\">&#8617;</a>"]
      blocks'  = if null blocks
                    then []
                    else let lastBlock   = last blocks
                             otherBlocks = init blocks
                         in  case lastBlock of
                                  (Para lst)  -> otherBlocks ++
                                                 [Para (lst ++ backlink)]
                                  (Plain lst) -> otherBlocks ++
                                                 [Plain (lst ++ backlink)]
                                  _           -> otherBlocks ++ [lastBlock,
                                                 Plain backlink]
  in  do contents <- blockListToHtml opts blocks'
         return $ li ! [identifier ("fn" ++ ref)] $ contents