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
|
{-
Copyright (C) 2006-7 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.Markdown
Copyright : Copyright (C) 2006-7 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Conversion of 'Pandoc' documents to markdown-formatted plain text.
Markdown: <http://daringfireball.net/projects/markdown/>
-}
module Text.Pandoc.Writers.Markdown ( writeMarkdown) where
import Text.Pandoc.Definition
import Text.Pandoc.Shared
import Text.Pandoc.Blocks
import Data.List ( group, isPrefixOf, drop, find, intersperse )
import Text.PrettyPrint.HughesPJ hiding ( Str )
import Control.Monad.State
type Notes = [[Block]]
type Refs = KeyTable
type WriterState = (Notes, Refs)
-- | Convert Pandoc to Markdown.
writeMarkdown :: WriterOptions -> Pandoc -> String
writeMarkdown opts document =
render $ evalState (pandocToMarkdown opts document) ([],[])
-- | Return markdown representation of document.
pandocToMarkdown :: WriterOptions -> Pandoc -> State WriterState Doc
pandocToMarkdown opts (Pandoc meta blocks) = do
let before = writerIncludeBefore opts
let after = writerIncludeAfter opts
let before' = if null before then empty else text before
let after' = if null after then empty else text after
metaBlock <- metaToMarkdown opts meta
let head = if writerStandalone opts
then metaBlock $+$ text (writerHeader opts)
else empty
let headerBlocks = filter isHeaderBlock blocks
let toc = if writerTableOfContents opts
then tableOfContents opts headerBlocks
else empty
body <- blockListToMarkdown opts blocks
(notes, _) <- get
notes' <- notesToMarkdown opts (reverse notes)
(_, refs) <- get -- note that the notes may contain refs
refs' <- keyTableToMarkdown opts (reverse refs)
return $ head $+$ before' $+$ toc $+$ body $+$ text "" $+$
notes' $+$ text "" $+$ refs' $+$ after'
-- | Return markdown representation of reference key table.
keyTableToMarkdown :: WriterOptions -> KeyTable -> State WriterState Doc
keyTableToMarkdown opts refs = mapM (keyToMarkdown opts) refs >>= return . vcat
-- | Return markdown representation of a reference key.
keyToMarkdown :: WriterOptions
-> ([Inline], (String, String))
-> State WriterState Doc
keyToMarkdown opts (label, (src, tit)) = do
label' <- inlineListToMarkdown opts label
let tit' = if null tit then empty else text $ " \"" ++ tit ++ "\""
return $ text " " <> char '[' <> label' <> char ']' <> text ": " <>
text src <> tit'
-- | Return markdown representation of notes.
notesToMarkdown :: WriterOptions -> [[Block]] -> State WriterState Doc
notesToMarkdown opts notes =
mapM (\(num, note) -> noteToMarkdown opts num note) (zip [1..] notes) >>=
return . vcat
-- | Return markdown representation of a note.
noteToMarkdown :: WriterOptions -> Int -> [Block] -> State WriterState Doc
noteToMarkdown opts num note = do
contents <- blockListToMarkdown opts note
let marker = text "[^" <> text (show num) <> text "]:"
return $ hang marker (writerTabStop opts) contents
wrappedMarkdown :: WriterOptions -> [Inline] -> State WriterState Doc
wrappedMarkdown opts sect = do
let chunks = splitBy Space sect
chunks' <- mapM (inlineListToMarkdown opts) chunks
return $ fsep chunks'
-- | Escape special characters for Markdown.
escapeString :: String -> String
escapeString = escapeStringUsing markdownEscapes
where markdownEscapes = ('\160', " "):(backslashEscapes "`<\\*_^~")
-- | Convert bibliographic information into Markdown header.
metaToMarkdown :: WriterOptions -> Meta -> State WriterState Doc
metaToMarkdown opts (Meta title authors date) = do
title' <- titleToMarkdown opts title
authors' <- authorsToMarkdown authors
date' <- dateToMarkdown date
return $ title' $+$ authors' $+$ date'
titleToMarkdown :: WriterOptions -> [Inline] -> State WriterState Doc
titleToMarkdown opts [] = return empty
titleToMarkdown opts lst = do
contents <- inlineListToMarkdown opts lst
return $ text "% " <> contents
authorsToMarkdown :: [String] -> State WriterState Doc
authorsToMarkdown [] = return empty
authorsToMarkdown lst = return $
text "% " <> text (joinWithSep ", " (map escapeString lst))
dateToMarkdown :: String -> State WriterState Doc
dateToMarkdown [] = return empty
dateToMarkdown str = return $ text "% " <> text (escapeString str)
-- | Construct table of contents from list of header blocks.
tableOfContents :: WriterOptions -> [Block] -> Doc
tableOfContents opts headers =
let opts' = opts { writerIgnoreNotes = True }
contents = BulletList $ map elementToListItem $ hierarchicalize headers
in evalState (blockToMarkdown opts' contents) ([],[])
-- | Converts an Element to a list item for a table of contents,
elementToListItem :: Element -> [Block]
elementToListItem (Blk _) = []
elementToListItem (Sec headerText subsecs) = [Plain headerText] ++
if null subsecs
then []
else [BulletList $ map elementToListItem subsecs]
-- | Convert Pandoc block element to markdown.
blockToMarkdown :: WriterOptions -- ^ Options
-> Block -- ^ Block element
-> State WriterState Doc
blockToMarkdown opts Null = return empty
blockToMarkdown opts (Plain inlines) = wrappedMarkdown opts inlines
blockToMarkdown opts (Para inlines) = do
contents <- wrappedMarkdown opts inlines
return $ contents <> text "\n"
blockToMarkdown opts (RawHtml str) = return $ text str
blockToMarkdown opts HorizontalRule = return $ text "\n* * * * *\n"
blockToMarkdown opts (Header level inlines) = do
contents <- inlineListToMarkdown opts inlines
return $ text ((replicate level '#') ++ " ") <> contents <> text "\n"
blockToMarkdown opts (CodeBlock str) = return $
(nest (writerTabStop opts) $ vcat $ map text (lines str)) <> text "\n"
blockToMarkdown opts (BlockQuote blocks) = do
contents <- blockListToMarkdown opts blocks
let quotedContents = unlines $ map ("> " ++) $ lines $ render contents
return $ text quotedContents
blockToMarkdown opts (Table caption aligns widths headers rows) = do
caption' <- inlineListToMarkdown opts caption
let caption'' = if null caption
then empty
else text "" $+$ (text "Table: " <> caption')
headers' <- mapM (blockListToMarkdown opts) headers
let widthsInChars = map (floor . (78 *)) widths
let alignHeader alignment = case alignment of
AlignLeft -> leftAlignBlock
AlignCenter -> centerAlignBlock
AlignRight -> rightAlignBlock
AlignDefault -> leftAlignBlock
let makeRow = hsepBlocks . (zipWith alignHeader aligns) .
(zipWith docToBlock widthsInChars)
let head = makeRow headers'
rows' <- mapM (\row -> do cols <- mapM (blockListToMarkdown opts) row
return $ makeRow cols) rows
let tableWidth = sum widthsInChars
let maxRowHeight = maximum $ map heightOfBlock (head:rows')
let isMultilineTable = maxRowHeight > 1
let underline = hsep $
map (\width -> text $ replicate width '-') widthsInChars
let border = if isMultilineTable
then text $ replicate (sum widthsInChars + (length widthsInChars - 1)) '-'
else empty
let spacer = if isMultilineTable
then text ""
else empty
let body = vcat $ intersperse spacer $ map blockToDoc rows'
return $ (nest 2 $ border $+$ (blockToDoc head) $+$ underline $+$ body $+$
border $+$ caption'') <> text "\n"
blockToMarkdown opts (BulletList items) = do
contents <- mapM (bulletListItemToMarkdown opts) items
return $ (vcat contents) <> text "\n"
blockToMarkdown opts (OrderedList attribs items) = do
let markers = orderedListMarkers attribs
let markers' = map (\m -> if length m < 3
then m ++ replicate (3 - length m) ' '
else m) markers
contents <- mapM (\(item, num) -> orderedListItemToMarkdown opts item num) $
zip markers' items
return $ (vcat contents) <> text "\n"
blockToMarkdown opts (DefinitionList items) = do
contents <- mapM (definitionListItemToMarkdown opts) items
return $ (vcat contents) <> text "\n"
-- | Convert bullet list item (list of blocks) to markdown.
bulletListItemToMarkdown :: WriterOptions -> [Block] -> State WriterState Doc
bulletListItemToMarkdown opts items = do
contents <- blockListToMarkdown opts items
return $ hang (text "- ") (writerTabStop opts) contents
-- | Convert ordered list item (a list of blocks) to markdown.
orderedListItemToMarkdown :: WriterOptions -- ^ options
-> String -- ^ list item marker
-> [Block] -- ^ list item (list of blocks)
-> State WriterState Doc
orderedListItemToMarkdown opts marker items = do
contents <- blockListToMarkdown opts items
return $ hang (text marker) (writerTabStop opts) contents
-- | Convert definition list item (label, list of blocks) to markdown.
definitionListItemToMarkdown :: WriterOptions
-> ([Inline],[Block])
-> State WriterState Doc
definitionListItemToMarkdown opts (label, items) = do
labelText <- inlineListToMarkdown opts label
let tabStop = writerTabStop opts
let leader = char ':'
contents <- mapM (\item -> blockToMarkdown opts item >>=
(\txt -> return (leader $$ nest tabStop txt)))
items >>= return . vcat
return $ labelText $+$ contents
-- | Convert list of Pandoc block elements to markdown.
blockListToMarkdown :: WriterOptions -- ^ Options
-> [Block] -- ^ List of block elements
-> State WriterState Doc
blockListToMarkdown opts blocks =
mapM (blockToMarkdown opts) blocks >>= return . vcat
-- | Get reference for target; if none exists, create unique one and return.
-- Prefer label if possible; otherwise, generate a unique key.
getReference :: [Inline] -> Target -> State WriterState [Inline]
getReference label (src, tit) = do
(_,refs) <- get
case find ((== (src, tit)) . snd) refs of
Just (ref, _) -> return ref
Nothing -> do
let label' = case find ((== label) . fst) refs of
Just _ -> -- label is used; generate numerical label
case find (\n -> not (any (== [Str (show n)])
(map fst refs))) [1..10000] of
Just x -> [Str (show x)]
Nothing -> error "no unique label"
Nothing -> label
modify (\(notes, refs) -> (notes, (label', (src,tit)):refs))
return label'
-- | Convert list of Pandoc inline elements to markdown.
inlineListToMarkdown :: WriterOptions -> [Inline] -> State WriterState Doc
inlineListToMarkdown opts lst =
mapM (inlineToMarkdown opts) lst >>= return . hcat
-- | Convert Pandoc inline element to markdown.
inlineToMarkdown :: WriterOptions -> Inline -> State WriterState Doc
inlineToMarkdown opts (Emph lst) = do
contents <- inlineListToMarkdown opts lst
return $ char '*' <> contents <> char '*'
inlineToMarkdown opts (Strong lst) = do
contents <- inlineListToMarkdown opts lst
return $ text "**" <> contents <> text "**"
inlineToMarkdown opts (Strikeout lst) = do
contents <- inlineListToMarkdown opts lst
return $ text "~~" <> contents <> text "~~"
inlineToMarkdown opts (Superscript lst) = do
contents <- inlineListToMarkdown opts lst
let contents' = text $ substitute " " "\\ " $ render contents
return $ char '^' <> contents' <> char '^'
inlineToMarkdown opts (Subscript lst) = do
contents <- inlineListToMarkdown opts lst
let contents' = text $ substitute " " "\\ " $ render contents
return $ char '~' <> contents' <> char '~'
inlineToMarkdown opts (Quoted SingleQuote lst) = do
contents <- inlineListToMarkdown opts lst
return $ char '\'' <> contents <> char '\''
inlineToMarkdown opts (Quoted DoubleQuote lst) = do
contents <- inlineListToMarkdown opts lst
return $ char '"' <> contents <> char '"'
inlineToMarkdown opts EmDash = return $ text "--"
inlineToMarkdown opts EnDash = return $ char '-'
inlineToMarkdown opts Apostrophe = return $ char '\''
inlineToMarkdown opts Ellipses = return $ text "..."
inlineToMarkdown opts (Code str) =
let tickGroups = filter (\s -> '`' `elem` s) $ group str
longest = if null tickGroups
then 0
else maximum $ map length tickGroups
marker = replicate (longest + 1) '`'
spacer = if (longest == 0) then "" else " " in
return $ text (marker ++ spacer ++ str ++ spacer ++ marker)
inlineToMarkdown opts (Str str) = return $ text $ escapeString str
inlineToMarkdown opts (TeX str) = return $ text str
inlineToMarkdown opts (HtmlInline str) = return $ text str
inlineToMarkdown opts (LineBreak) = return $ text " \n"
inlineToMarkdown opts Space = return $ char ' '
inlineToMarkdown opts (Link txt (src, tit)) = do
linktext <- inlineListToMarkdown opts txt
let linktitle = if null tit then empty else text $ " \"" ++ tit ++ "\""
let srcSuffix = if isPrefixOf "mailto:" src then drop 7 src else src
let useRefLinks = writerReferenceLinks opts
let useAuto = null tit && txt == [Code srcSuffix]
ref <- if useRefLinks then getReference txt (src, tit) else return []
reftext <- inlineListToMarkdown opts ref
return $ if useAuto
then char '<' <> text srcSuffix <> char '>'
else if useRefLinks
then let first = char '[' <> linktext <> char ']'
second = if txt == ref
then text "[]"
else char '[' <> reftext <> char ']'
in first <> second
else char '[' <> linktext <> char ']' <>
char '(' <> text src <> linktitle <> char ')'
inlineToMarkdown opts (Image alternate (source, tit)) = do
let txt = if (null alternate) || (alternate == [Str ""]) ||
(alternate == [Str source]) -- to prevent autolinks
then [Str "image"]
else alternate
linkPart <- inlineToMarkdown opts (Link txt (source, tit))
return $ char '!' <> linkPart
inlineToMarkdown opts (Note contents) = do
modify (\(notes, refs) -> (contents:notes, refs)) -- add to notes in state
(notes, _) <- get
let ref = show $ (length notes)
return $ text "[^" <> text ref <> char ']'
|