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Diffstat (limited to 'src/Text/Pandoc/Readers/RST.hs')
| -rw-r--r-- | src/Text/Pandoc/Readers/RST.hs | 640 |
1 files changed, 640 insertions, 0 deletions
diff --git a/src/Text/Pandoc/Readers/RST.hs b/src/Text/Pandoc/Readers/RST.hs new file mode 100644 index 000000000..1239eb688 --- /dev/null +++ b/src/Text/Pandoc/Readers/RST.hs @@ -0,0 +1,640 @@ +{- +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.Readers.RST + 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 from reStructuredText to 'Pandoc' document. +-} +module Text.Pandoc.Readers.RST ( + readRST + ) where +import Text.Pandoc.Definition +import Text.Pandoc.Shared +import Text.ParserCombinators.Parsec +import Data.List ( findIndex, delete ) + +-- | Parse reStructuredText string and return Pandoc document. +readRST :: ParserState -> String -> Pandoc +readRST state str = (readWith parseRST) state (str ++ "\n\n") + +-- +-- Constants and data structure definitions +--- + +bulletListMarkers = "*+-" +underlineChars = "!\"#$&'()*+,-./:;<=>?@[\\]^_`{|}~" + +-- treat these as potentially non-text when parsing inline: +specialChars = "\\`|*_<>$:[-" + +-- +-- parsing documents +-- + +isAnonKey (ref, src) = ref == [Str "_"] + +isHeader :: Int -> Block -> Bool +isHeader n (Header x _) = x == n +isHeader _ _ = False + +-- | Promote all headers in a list of blocks. (Part of +-- title transformation for RST.) +promoteHeaders :: Int -> [Block] -> [Block] +promoteHeaders num ((Header level text):rest) = + (Header (level - num) text):(promoteHeaders num rest) +promoteHeaders num (other:rest) = other:(promoteHeaders num rest) +promoteHeaders num [] = [] + +-- | If list of blocks starts with a header (or a header and subheader) +-- of level that are not found elsewhere, return it as a title and +-- promote all the other headers. +titleTransform :: [Block] -- ^ list of blocks + -> ([Block], [Inline]) -- ^ modified list of blocks, title +titleTransform ((Header 1 head1):(Header 2 head2):rest) = -- title subtitle + if (any (isHeader 1) rest) || (any (isHeader 2) rest) + then ((Header 1 head1):(Header 2 head2):rest, []) + else ((promoteHeaders 2 rest), head1 ++ [Str ":", Space] ++ head2) +titleTransform ((Header 1 head1):rest) = -- title, no subtitle + if (any (isHeader 1) rest) + then ((Header 1 head1):rest, []) + else ((promoteHeaders 1 rest), head1) +titleTransform blocks = (blocks, []) + +parseRST = do + startPos <- getPosition + -- go through once just to get list of reference keys + -- docMinusKeys is the raw document with blanks where the keys were... + docMinusKeys <- manyTill (referenceKey <|> lineClump) eof >>= return . concat + setInput docMinusKeys + setPosition startPos + st <- getState + let reversedKeys = stateKeys st + updateState $ \st -> st { stateKeys = reverse reversedKeys } + -- now parse it for real... + blocks <- parseBlocks + let blocks' = filter (/= Null) blocks + state <- getState + let (blocks'', title) = if stateStandalone state + then titleTransform blocks' + else (blocks', []) + let authors = stateAuthors state + let date = stateDate state + let title' = if (null title) then (stateTitle state) else title + return $ Pandoc (Meta title' authors date) blocks'' + +-- +-- parsing blocks +-- + +parseBlocks = manyTill block eof + +block = choice [ codeBlock + , rawHtmlBlock + , rawLaTeXBlock + , fieldList + , blockQuote + , imageBlock + , unknownDirective + , header + , hrule + , list + , lineBlock + , para + , plain + , nullBlock ] <?> "block" + +-- +-- field list +-- + +fieldListItem indent = try $ do + string indent + char ':' + name <- many1 alphaNum + string ": " + skipSpaces + first <- manyTill anyChar newline + rest <- option "" $ try $ lookAhead (string indent >> oneOf " \t") >> + indentedBlock + return (name, joinWithSep " " (first:(lines rest))) + +fieldList = try $ do + indent <- lookAhead $ many (oneOf " \t") + items <- many1 $ fieldListItem indent + blanklines + let authors = case lookup "Authors" items of + Just auth -> [auth] + Nothing -> map snd (filter (\(x,y) -> x == "Author") items) + if null authors + then return () + else updateState $ \st -> st {stateAuthors = authors} + case (lookup "Date" items) of + Just dat -> updateState $ \st -> st {stateDate = dat} + Nothing -> return () + case (lookup "Title" items) of + Just tit -> parseFromString (many inline) tit >>= + \t -> updateState $ \st -> st {stateTitle = t} + Nothing -> return () + let remaining = filter (\(x,y) -> (x /= "Authors") && (x /= "Author") && + (x /= "Date") && (x /= "Title")) items + if null remaining + then return Null + else do terms <- mapM (return . (:[]) . Str . fst) remaining + defs <- mapM (parseFromString (many block) . snd) + remaining + return $ DefinitionList $ zip terms defs + +-- +-- line block +-- + +lineBlockLine = try $ do + string "| " + white <- many (oneOf " \t") + line <- manyTill inline newline + return $ (if null white then [] else [Str white]) ++ line ++ [LineBreak] + +lineBlock = try $ do + lines <- many1 lineBlockLine + blanklines + return $ Para (concat lines) + +-- +-- paragraph block +-- + +para = paraBeforeCodeBlock <|> paraNormal <?> "paragraph" + +codeBlockStart = string "::" >> blankline >> blankline + +-- paragraph that ends in a :: starting a code block +paraBeforeCodeBlock = try $ do + result <- many1 (notFollowedBy' codeBlockStart >> inline) + lookAhead (string "::") + return $ Para $ if last result == Space + then normalizeSpaces result + else (normalizeSpaces result) ++ [Str ":"] + +-- regular paragraph +paraNormal = try $ do + result <- many1 inline + newline + blanklines + return $ Para $ normalizeSpaces result + +plain = many1 inline >>= return . Plain . normalizeSpaces + +-- +-- image block +-- + +imageBlock = try $ do + string ".. image:: " + src <- manyTill anyChar newline + fields <- option [] $ do indent <- lookAhead $ many (oneOf " /t") + many1 $ fieldListItem indent + optional blanklines + case lookup "alt" fields of + Just alt -> return $ Plain [Image [Str alt] (src, alt)] + Nothing -> return $ Plain [Image [Str "image"] (src, "")] +-- +-- header blocks +-- + +header = doubleHeader <|> singleHeader <?> "header" + +-- a header with lines on top and bottom +doubleHeader = try $ do + c <- oneOf underlineChars + rest <- many (char c) -- the top line + let lenTop = length (c:rest) + skipSpaces + newline + txt <- many1 (notFollowedBy blankline >> inline) + pos <- getPosition + let len = (sourceColumn pos) - 1 + if (len > lenTop) then fail "title longer than border" else return () + blankline -- spaces and newline + count lenTop (char c) -- the bottom line + blanklines + -- check to see if we've had this kind of header before. + -- if so, get appropriate level. if not, add to list. + state <- getState + let headerTable = stateHeaderTable state + let (headerTable',level) = case findIndex (== DoubleHeader c) headerTable of + Just ind -> (headerTable, ind + 1) + Nothing -> (headerTable ++ [DoubleHeader c], (length headerTable) + 1) + setState (state { stateHeaderTable = headerTable' }) + return $ Header level (normalizeSpaces txt) + +-- a header with line on the bottom only +singleHeader = try $ do + notFollowedBy' whitespace + txt <- many1 (do {notFollowedBy blankline; inline}) + pos <- getPosition + let len = (sourceColumn pos) - 1 + blankline + c <- oneOf underlineChars + rest <- count (len - 1) (char c) + many (char c) + blanklines + state <- getState + let headerTable = stateHeaderTable state + let (headerTable',level) = case findIndex (== SingleHeader c) headerTable of + Just ind -> (headerTable, ind + 1) + Nothing -> (headerTable ++ [SingleHeader c], (length headerTable) + 1) + setState (state { stateHeaderTable = headerTable' }) + return $ Header level (normalizeSpaces txt) + +-- +-- hrule block +-- + +hrule = try $ do + chr <- oneOf underlineChars + count 3 (char chr) + skipMany (char chr) + blankline + blanklines + return HorizontalRule + +-- +-- code blocks +-- + +-- read a line indented by a given string +indentedLine indents = try $ do + string indents + result <- manyTill anyChar newline + return $ result ++ "\n" + +-- two or more indented lines, possibly separated by blank lines. +-- any amount of indentation will work. +indentedBlock = do + indents <- lookAhead $ many1 (oneOf " \t") + lns <- many $ choice $ [ indentedLine indents, + try $ do b <- blanklines + l <- indentedLine indents + return (b ++ l) ] + optional blanklines + return $ concat lns + +codeBlock = try $ do + codeBlockStart + result <- indentedBlock + return $ CodeBlock $ stripTrailingNewlines result + +-- +-- raw html +-- + +rawHtmlBlock = try $ string ".. raw:: html" >> blanklines >> + indentedBlock >>= return . RawHtml + +-- +-- raw latex +-- + +rawLaTeXBlock = try $ do + string ".. raw:: latex" + blanklines + result <- indentedBlock + return $ Para [(TeX result)] + +-- +-- block quotes +-- + +blockQuote = do + raw <- indentedBlock + -- parse the extracted block, which may contain various block elements: + contents <- parseFromString parseBlocks $ raw ++ "\n\n" + return $ BlockQuote contents + +-- +-- list blocks +-- + +list = choice [ bulletList, orderedList, definitionList ] <?> "list" + +definitionListItem = try $ do + term <- many1Till inline endline + raw <- indentedBlock + -- parse the extracted block, which may contain various block elements: + contents <- parseFromString parseBlocks $ raw ++ "\n\n" + return (normalizeSpaces term, contents) + +definitionList = many1 definitionListItem >>= return . DefinitionList + +-- parses bullet list start and returns its length (inc. following whitespace) +bulletListStart = try $ do + notFollowedBy' hrule -- because hrules start out just like lists + marker <- oneOf bulletListMarkers + white <- many1 spaceChar + return $ length (marker:white) + +-- parses ordered list start and returns its length (inc following whitespace) +orderedListStart style delim = try $ do + (_, markerLen) <- withHorizDisplacement (orderedListMarker style delim) + white <- many1 spaceChar + return $ markerLen + length white + +-- parse a line of a list item +listLine markerLength = try $ do + notFollowedBy blankline + indentWith markerLength + line <- manyTill anyChar newline + return $ line ++ "\n" + +-- indent by specified number of spaces (or equiv. tabs) +indentWith num = do + state <- getState + let tabStop = stateTabStop state + if (num < tabStop) + then count num (char ' ') + else choice [ try (count num (char ' ')), + (try (char '\t' >> count (num - tabStop) (char ' '))) ] + +-- parse raw text for one list item, excluding start marker and continuations +rawListItem start = do + markerLength <- start + firstLine <- manyTill anyChar newline + restLines <- many (listLine markerLength) + return (markerLength, (firstLine ++ "\n" ++ (concat restLines))) + +-- continuation of a list item - indented and separated by blankline or +-- (in compact lists) endline. +-- Note: nested lists are parsed as continuations. +listContinuation markerLength = try $ do + blanks <- many1 blankline + result <- many1 (listLine markerLength) + return $ blanks ++ concat result + +listItem start = try $ do + (markerLength, first) <- rawListItem start + rest <- many (listContinuation markerLength) + blanks <- choice [ try (many blankline >>~ lookAhead start), + many1 blankline ] -- whole list must end with blank. + -- parsing with ListItemState forces markers at beginning of lines to + -- count as list item markers, even if not separated by blank space. + -- see definition of "endline" + state <- getState + let oldContext = stateParserContext state + setState $ state {stateParserContext = ListItemState} + -- parse the extracted block, which may itself contain block elements + parsed <- parseFromString parseBlocks $ concat (first:rest) ++ blanks + updateState (\st -> st {stateParserContext = oldContext}) + return parsed + +orderedList = do + (start, style, delim) <- lookAhead (anyOrderedListMarker >>~ spaceChar) + items <- many1 (listItem (orderedListStart style delim)) + let items' = compactify items + return $ OrderedList (start, style, delim) items' + +bulletList = many1 (listItem bulletListStart) >>= + return . BulletList . compactify + +-- +-- unknown directive (e.g. comment) +-- + +unknownDirective = try $ do + string ".. " + manyTill anyChar newline + many (string " :" >> many1 (noneOf "\n:") >> char ':' >> + many1 (noneOf "\n") >> newline) + optional blanklines + return Null + +-- +-- reference key +-- + +referenceKey = do + startPos <- getPosition + key <- choice [imageKey, anonymousKey, regularKeyQuoted, regularKey] + st <- getState + let oldkeys = stateKeys st + updateState $ \st -> st { stateKeys = key : oldkeys } + optional blanklines + endPos <- getPosition + -- return enough blanks to replace key + return $ replicate (sourceLine endPos - sourceLine startPos) '\n' + +targetURI = do + skipSpaces + optional newline + contents <- many1 (try (many spaceChar >> newline >> + many1 spaceChar >> noneOf " \t\n") <|> noneOf "\n") + blanklines + return contents + +imageKey = try $ do + string ".. |" + ref <- manyTill inline (char '|') + skipSpaces + string "image::" + src <- targetURI + return (normalizeSpaces ref, (removeLeadingTrailingSpace src, "")) + +anonymousKey = try $ do + oneOfStrings [".. __:", "__"] + src <- targetURI + state <- getState + return ([Str "_"], (removeLeadingTrailingSpace src, "")) + +regularKeyQuoted = try $ do + string ".. _`" + ref <- manyTill inline (char '`') + char ':' + src <- targetURI + return (normalizeSpaces ref, (removeLeadingTrailingSpace src, "")) + +regularKey = try $ do + string ".. _" + ref <- manyTill inline (char ':') + src <- targetURI + return (normalizeSpaces ref, (removeLeadingTrailingSpace src, "")) + + -- + -- inline + -- + +inline = choice [ link + , str + , whitespace + , endline + , strong + , emph + , code + , image + , hyphens + , superscript + , subscript + , escapedChar + , symbol ] <?> "inline" + +hyphens = do + result <- many1 (char '-') + option Space endline + -- don't want to treat endline after hyphen or dash as a space + return $ Str result + +escapedChar = escaped anyChar + +symbol = do + result <- oneOf specialChars + return $ Str [result] + +-- parses inline code, between codeStart and codeEnd +code = try $ do + string "``" + result <- manyTill anyChar (try (string "``")) + return $ Code $ removeLeadingTrailingSpace $ joinWithSep " " $ lines result + +emph = enclosed (char '*') (char '*') inline >>= + return . Emph . normalizeSpaces + +strong = enclosed (string "**") (try $ string "**") inline >>= + return . Strong . normalizeSpaces + +interpreted role = try $ do + optional $ try $ string "\\ " + result <- enclosed (string $ ":" ++ role ++ ":`") (char '`') anyChar + nextChar <- lookAhead anyChar + try (string "\\ ") <|> lookAhead (count 1 $ oneOf " \t\n") <|> (eof >> return "") + return [Str result] + +superscript = interpreted "sup" >>= (return . Superscript) + +subscript = interpreted "sub" >>= (return . Subscript) + +whitespace = many1 spaceChar >> return Space <?> "whitespace" + +str = notFollowedBy' oneWordReference >> + many1 (noneOf (specialChars ++ "\t\n ")) >>= return . Str + +-- an endline character that can be treated as a space, not a structural break +endline = try $ do + newline + notFollowedBy blankline + -- parse potential list-starts at beginning of line differently in a list: + st <- getState + if (stateParserContext st) == ListItemState + then notFollowedBy (anyOrderedListMarker >> spaceChar) >> + notFollowedBy' bulletListStart + else return () + return Space + +-- +-- links +-- + +link = choice [explicitLink, referenceLink, autoLink] <?> "link" + +explicitLink = try $ do + char '`' + notFollowedBy (char '`') -- `` is marks start of inline code + label <- manyTill inline (try (do {spaces; char '<'})) + src <- manyTill (noneOf ">\n ") (char '>') + skipSpaces + string "`_" + return $ Link (normalizeSpaces label) (removeLeadingTrailingSpace src, "") + +reference = try $ do + char '`' + notFollowedBy (char '`') + label <- many1Till inline (char '`') + char '_' + return label + +oneWordReference = do + raw <- many1 alphaNum + char '_' + notFollowedBy alphaNum -- because this_is_not a link + return [Str raw] + +referenceLink = try $ do + label <- reference <|> oneWordReference + key <- option label (do{char '_'; return [Str "_"]}) -- anonymous link + state <- getState + let keyTable = stateKeys state + src <- case lookupKeySrc keyTable key of + Nothing -> fail "no corresponding key" + Just target -> return target + -- if anonymous link, remove first anon key so it won't be used again + let keyTable' = if (key == [Str "_"]) -- anonymous link? + then delete ([Str "_"], src) keyTable -- remove first anon key + else keyTable + setState $ state { stateKeys = keyTable' } + return $ Link (normalizeSpaces label) src + +uriScheme = oneOfStrings [ "http://", "https://", "ftp://", "file://", + "mailto:", "news:", "telnet:" ] + +uri = try $ do + scheme <- uriScheme + identifier <- many1 (noneOf " \t\n") + return $ scheme ++ identifier + +autoURI = do + src <- uri + return $ Link [Str src] (src, "") + +emailChar = alphaNum <|> oneOf "-+_." + +emailAddress = try $ do + firstLetter <- alphaNum + restAddr <- many emailChar + let addr = firstLetter:restAddr + char '@' + dom <- domain + return $ addr ++ '@':dom + +domainChar = alphaNum <|> char '-' + +domain = do + first <- many1 domainChar + dom <- many1 (try (do{ char '.'; many1 domainChar })) + return $ joinWithSep "." (first:dom) + +autoEmail = do + src <- emailAddress + return $ Link [Str src] ("mailto:" ++ src, "") + +autoLink = autoURI <|> autoEmail + +-- For now, we assume that all substitution references are for images. +image = try $ do + char '|' + ref <- manyTill inline (char '|') + state <- getState + let keyTable = stateKeys state + src <- case lookupKeySrc keyTable ref of + Nothing -> fail "no corresponding key" + Just target -> return target + return $ Image (normalizeSpaces ref) src + |