{- Copyright (C) 2006-7 John MacFarlane 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 Stability : alpha Portability : portable Conversion from reStructuredText to 'Pandoc' document. -} module Text.Pandoc.Readers.RST ( readRST ) where import Text.Pandoc.Definition import Text.Pandoc.ParserCombinators import Text.Pandoc.Shared import Text.Pandoc.Readers.HTML ( anyHtmlBlockTag, anyHtmlInlineTag ) import Text.Regex ( matchRegex, mkRegex ) import Text.ParserCombinators.Parsec import Data.Maybe ( fromMaybe ) import Data.List ( findIndex, delete ) import Data.Char ( toUpper ) -- | Parse reStructuredText string and return Pandoc document. readRST :: ParserState -> String -> Pandoc readRST state str = (readWith parseRST) state (str ++ "\n\n") -- | Parse a string and print result (for testing). testString :: String -> IO () testString = testStringWith parseRST -- -- Constants and data structure definitions --- bulletListMarkers = "*+-" underlineChars = "!\"#$&'()*+,-./:;<=>?@[\\]^_`{|}~" -- treat these as potentially non-text when parsing inline: specialChars = "\\`|*_<>$:[-" -- -- parsing documents -- isAnonKey (ref, src) = (ref == [Str "_"]) isHeader1 :: Block -> Bool isHeader1 (Header 1 _) = True isHeader1 _ = False isHeader2 :: Block -> Bool isHeader2 (Header 2 _) = True isHeader2 _ = 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 isHeader1 rest) || (any isHeader2 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 isHeader1 rest) then ((Header 1 head1):rest, []) else ((promoteHeaders 1 rest), head1) titleTransform blocks = (blocks, []) parseRST = do -- first pass: get anonymous keys refs <- manyTill (referenceKey <|> (do l <- lineClump return (LineClump l))) eof let keys = map (\(KeyBlock label target) -> (label, target)) $ filter isKeyBlock refs let rawlines = map (\(LineClump ln) -> ln) $ filter isLineClump refs setInput $ concat rawlines -- with keys stripped out updateState (\state -> state { stateKeys = keys }) 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, blockQuote, imageBlock, unknownDirective, header, hrule, list, fieldList, lineBlock, para, plain, nullBlock ] "block" -- -- field list -- fieldListItem = try (do char ':' name <- many1 alphaNum string ": " skipSpaces first <- manyTill anyChar newline rest <- many (do notFollowedBy (char ':') notFollowedBy blankline skipSpaces manyTill anyChar newline ) return (name, (joinWithSep " " (first:rest)))) fieldList = try (do items <- many1 fieldListItem blanklines let authors = case (lookup "Authors" items) of Just auth -> [auth] Nothing -> map snd (filter (\(x,y) -> x == "Author") items) let date = case (lookup "Date" items) of Just dat -> dat Nothing -> "" let title = case (lookup "Title" items) of Just tit -> [Str tit] Nothing -> [] let remaining = filter (\(x,y) -> (x /= "Authors") && (x /= "Author") && (x /= "Date") && (x /= "Title")) items let result = map (\(x,y) -> Para [Strong [Str x], Str ":", Space, Str y]) remaining updateState (\st -> st { stateAuthors = authors, stateDate = date, stateTitle = title }) return (BlockQuote result)) -- -- line block -- lineBlockLine = try (do string "| " white <- many (oneOf " \t") line <- manyTill inline newline let line' = (if null white then [] else [Str white]) ++ line ++ [LineBreak] return line') lineBlock = try (do lines <- many1 lineBlockLine blanklines return $ Para (concat lines)) -- -- paragraph block -- para = choice [ paraBeforeCodeBlock, paraNormal ] "paragraph" codeBlockStart = try (do string "::" blankline blankline) -- paragraph that ends in a :: starting a code block paraBeforeCodeBlock = try (do result <- many1 (do {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 let result' = normalizeSpaces result return (Para result')) plain = do result <- many1 inline let result' = normalizeSpaces result return (Plain result') -- -- image block -- imageBlock = try (do string ".. image:: " src <- manyTill anyChar newline return (Plain [Image [Str "image"] (src, "")])) -- -- header blocks -- header = choice [ 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 (do {notFollowedBy blankline; inline}) pos <- getPosition let len = (sourceColumn pos) - 1 if (len > lenTop) then fail "title longer than border" else (do {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 -- hruleWith chr = try (do count 4 (char chr) skipMany (char chr) skipSpaces newline blanklines return HorizontalRule) hrule = choice (map hruleWith underlineChars) "hrule" -- -- 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 -- if variable = True, then any indent will work, but it must be consistent through the block -- if variable = False, indent should be one tab or equivalent in spaces indentedBlock variable = try (do state <- getState let tabStop = stateTabStop state indents <- if variable then many1 (oneOf " \t") else oneOfStrings ["\t", (replicate tabStop ' ')] firstline <- manyTill anyChar newline rest <- many (choice [ indentedLine indents, try (do b <- blanklines l <- indentedLine indents return (b ++ l))]) option "" blanklines return (firstline ++ "\n" ++ (concat rest))) codeBlock = try (do codeBlockStart result <- indentedBlock False -- the False means we want one tab stop indent on each line return (CodeBlock (stripTrailingNewlines result))) -- -- raw html -- rawHtmlBlock = try (do string ".. raw:: html" blanklines result <- indentedBlock True return (RawHtml result)) -- -- raw latex -- rawLaTeXBlock = try (do string ".. raw:: latex" blanklines result <- indentedBlock True return (Para [(TeX result)])) -- -- block quotes -- blockQuote = try (do raw <- indentedBlock True -- parse the extracted block, which may contain various block elements: rest <- getInput setInput $ raw ++ "\n\n" contents <- parseBlocks setInput rest return (BlockQuote contents)) -- -- list blocks -- list = choice [ bulletList, orderedList, definitionList ] "list" definitionListItem = try $ do term <- many1Till inline endline raw <- indentedBlock True -- parse the extracted block, which may contain various block elements: rest <- getInput setInput $ raw ++ "\n\n" contents <- parseBlocks setInput rest return (normalizeSpaces term, contents) definitionList = try $ do items <- many1 definitionListItem return (DefinitionList items) -- 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 let len = length (marker:white) return len) -- 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 (do {char '\t'; count (num - tabStop) (char ' ')})) ] -- parse raw text for one list item, excluding start marker and continuations rawListItem start = try $ 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 (do b <- many blankline lookAhead start return b), 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 remaining <- getInput setState $ state {stateParserContext = ListItemState} -- parse the extracted block, which may itself contain block elements setInput $ concat (first:rest) ++ blanks parsed <- parseBlocks setInput remaining updateState (\st -> st {stateParserContext = oldContext}) return parsed) orderedList = try $ do (start, style, delim) <- lookAhead anyOrderedListMarker items <- many1 (listItem (orderedListStart style delim)) let items' = compactify items return (OrderedList (start, style, delim) items') bulletList = try (do items <- many1 (listItem bulletListStart) let items' = compactify items return (BulletList items')) -- -- unknown directive (e.g. comment) -- unknownDirective = try (do string ".. " manyTill anyChar newline many (do string " " char ':' many1 (noneOf "\n:") char ':' many1 (noneOf "\n") newline) option "" blanklines return Null) -- -- reference key -- referenceKey = do result <- choice [imageKey, anonymousKey, regularKeyQuoted, regularKey] option "" blanklines return result targetURI = try $ do skipSpaces option ' ' newline contents <- many1 (try (do 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 $ KeyBlock (normalizeSpaces ref) (removeLeadingTrailingSpace src, "") anonymousKey = try $ do oneOfStrings [".. __:", "__"] src <- targetURI state <- getState return $ KeyBlock [Str "_"] (removeLeadingTrailingSpace src, "") regularKeyQuoted = try $ do string ".. _`" ref <- manyTill inline (char '`') char ':' src <- targetURI return $ KeyBlock (normalizeSpaces ref) (removeLeadingTrailingSpace src, "") regularKey = try $ do string ".. _" ref <- manyTill inline (char ':') src <- targetURI return $ KeyBlock (normalizeSpaces ref) (removeLeadingTrailingSpace src, "") -- -- inline -- inline = choice [ superscript, subscript, escapedChar, link, image, hyphens, strong, emph, code, str, tabchar, whitespace, endline, symbol ] "inline" hyphens = try (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 "``")) let result' = removeLeadingTrailingSpace $ joinWithSep " " $ lines result return (Code result')) emph = do result <- enclosed (char '*') (char '*') inline return (Emph (normalizeSpaces result)) strong = do result <- enclosed (string "**") (string "**") inline return (Strong (normalizeSpaces result)) interpreted role = try $ do option "" (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 = do many1 spaceChar "whitespace" return Space tabchar = do tab return (Str "\t") str = do notFollowedBy' oneWordReference result <- many1 (noneOf (specialChars ++ "\t\n ")) return (Str result) -- 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 do notFollowedBy' anyOrderedListMarker notFollowedBy' bulletListStart else option () pzero 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 = try $ 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 = try (do first <- many1 domainChar dom <- many1 (try (do{ char '.'; many1 domainChar })) return (joinWithSep "." (first:dom))) autoEmail = try $ 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)