{-# LANGUAGE CPP #-} {-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE ViewPatterns #-} -- | -- Module : Documentation.Haddock.Parser -- Copyright : (c) Mateusz Kowalczyk 2013-2014, -- Simon Hengel 2013 -- License : BSD-like -- -- Maintainer : haddock@projects.haskell.org -- Stability : experimental -- Portability : portable -- -- Parser used for Haddock comments. For external users of this -- library, the most commonly used combination of functions is going -- to be -- -- @'toRegular' . '_doc' . 'parseParas'@ module Documentation.Haddock.Parser ( parseString, parseParas, overIdentifier, toRegular, Identifier ) where import Control.Applicative import Control.Arrow (first) import Control.Monad import Data.Char (chr, isUpper, isAlpha, isAlphaNum, isSpace) import Data.List (intercalate, unfoldr, elemIndex) import Data.Maybe (fromMaybe, mapMaybe) import Data.Monoid import qualified Data.Set as Set import Documentation.Haddock.Doc import Documentation.Haddock.Markup ( markup, plainMarkup ) import Documentation.Haddock.Parser.Monad import Documentation.Haddock.Parser.Util import Documentation.Haddock.Types import Prelude hiding (takeWhile) import qualified Prelude as P import qualified Text.Parsec as Parsec import Text.Parsec (try) import qualified Data.Text as T import Data.Text (Text) #if MIN_VERSION_base(4,9,0) import Text.Read.Lex (isSymbolChar) #else import Data.Char (GeneralCategory (..), generalCategory) #endif -- $setup -- >>> :set -XOverloadedStrings #if !MIN_VERSION_base(4,9,0) -- inlined from base-4.10.0.0 isSymbolChar :: Char -> Bool isSymbolChar c = not (isPuncChar c) && case generalCategory c of MathSymbol -> True CurrencySymbol -> True ModifierSymbol -> True OtherSymbol -> True DashPunctuation -> True OtherPunctuation -> c `notElem` ("'\"" :: String) ConnectorPunctuation -> c /= '_' _ -> False where -- | The @special@ character class as defined in the Haskell Report. isPuncChar :: Char -> Bool isPuncChar = (`elem` (",;()[]{}`" :: String)) #endif -- | Identifier string surrounded with opening and closing quotes/backticks. type Identifier = (Char, String, Char) -- | Drops the quotes/backticks around all identifiers, as if they -- were valid but still 'String's. toRegular :: DocH mod Identifier -> DocH mod String toRegular = fmap (\(_, x, _) -> x) -- | Maps over 'DocIdentifier's over 'String' with potentially failing -- conversion using user-supplied function. If the conversion fails, -- the identifier is deemed to not be valid and is treated as a -- regular string. overIdentifier :: (String -> Maybe a) -> DocH mod Identifier -> DocH mod a overIdentifier f d = g d where g (DocIdentifier (o, x, e)) = case f x of Nothing -> DocString $ o : x ++ [e] Just x' -> DocIdentifier x' g DocEmpty = DocEmpty g (DocAppend x x') = DocAppend (g x) (g x') g (DocString x) = DocString x g (DocParagraph x) = DocParagraph $ g x g (DocIdentifierUnchecked x) = DocIdentifierUnchecked x g (DocModule x) = DocModule x g (DocWarning x) = DocWarning $ g x g (DocEmphasis x) = DocEmphasis $ g x g (DocMonospaced x) = DocMonospaced $ g x g (DocBold x) = DocBold $ g x g (DocUnorderedList x) = DocUnorderedList $ fmap g x g (DocOrderedList x) = DocOrderedList $ fmap g x g (DocDefList x) = DocDefList $ fmap (\(y, z) -> (g y, g z)) x g (DocCodeBlock x) = DocCodeBlock $ g x g (DocHyperlink (Hyperlink u x)) = DocHyperlink (Hyperlink u (fmap g x)) g (DocPic x) = DocPic x g (DocMathInline x) = DocMathInline x g (DocMathDisplay x) = DocMathDisplay x g (DocAName x) = DocAName x g (DocProperty x) = DocProperty x g (DocExamples x) = DocExamples x g (DocHeader (Header l x)) = DocHeader . Header l $ g x g (DocTable (Table h b)) = DocTable (Table (map (fmap g) h) (map (fmap g) b)) choice' :: [Parser a] -> Parser a choice' [] = empty choice' [p] = p choice' (p : ps) = try p <|> choice' ps parse :: Parser a -> Text -> (ParserState, a) parse p = either err id . parseOnly (p <* Parsec.eof) where err = error . ("Haddock.Parser.parse: " ++) -- | Main entry point to the parser. Appends the newline character -- to the input string. parseParas :: Maybe Package -> String -- ^ String to parse -> MetaDoc mod Identifier parseParas pkg input = case parseParasState input of (state, a) -> MetaDoc { _meta = Meta { _version = parserStateSince state , _package = pkg } , _doc = a } parseParasState :: String -> (ParserState, DocH mod Identifier) parseParasState = parse (emptyLines *> p) . T.pack . (++ "\n") . filter (/= '\r') where p :: Parser (DocH mod Identifier) p = docConcat <$> many (paragraph <* emptyLines) emptyLines :: Parser () emptyLines = void $ many (try (skipHorizontalSpace *> "\n")) parseParagraphs :: String -> Parser (DocH mod Identifier) parseParagraphs input = case parseParasState input of (state, a) -> Parsec.putState state *> pure a -- | Variant of 'parseText' for 'String' instead of 'Text' parseString :: String -> DocH mod Identifier parseString = parseText . T.pack -- | Parse a text paragraph. Actually just a wrapper over 'parseParagraph' which -- drops leading whitespace. parseText :: Text -> DocH mod Identifier parseText = parseParagraph . T.dropWhile isSpace . T.filter (/= '\r') parseParagraph :: Text -> DocH mod Identifier parseParagraph = snd . parse p where p :: Parser (DocH mod Identifier) p = docConcat <$> many (choice' [ monospace , anchor , identifier , moduleName , picture , mathDisplay , mathInline , markdownImage , hyperlink , bold , emphasis , encodedChar , string' , skipSpecialChar ]) -- | Parses and processes -- <https://en.wikipedia.org/wiki/Numeric_character_reference Numeric character references> -- -- >>> parseString "A" -- DocString "A" encodedChar :: Parser (DocH mod a) encodedChar = "&#" *> c <* ";" where c = DocString . return . chr <$> num num = hex <|> decimal hex = ("x" <|> "X") *> hexadecimal -- | List of characters that we use to delimit any special markup. -- Once we have checked for any of these and tried to parse the -- relevant markup, we can assume they are used as regular text. specialChar :: [Char] specialChar = "_/<@\"&'`# " -- | Plain, regular parser for text. Called as one of the last parsers -- to ensure that we have already given a chance to more meaningful parsers -- before capturing their characers. string' :: Parser (DocH mod a) string' = DocString . unescape . T.unpack <$> takeWhile1_ (`notElem` specialChar) where unescape "" = "" unescape ('\\':x:xs) = x : unescape xs unescape (x:xs) = x : unescape xs -- | Skips a single special character and treats it as a plain string. -- This is done to skip over any special characters belonging to other -- elements but which were not deemed meaningful at their positions. skipSpecialChar :: Parser (DocH mod a) skipSpecialChar = DocString . return <$> Parsec.oneOf specialChar -- | Emphasis parser. -- -- >>> parseString "/Hello world/" -- DocEmphasis (DocString "Hello world") emphasis :: Parser (DocH mod Identifier) emphasis = DocEmphasis . parseParagraph <$> disallowNewline ("/" *> takeWhile1_ (/= '/') <* "/") -- | Bold parser. -- -- >>> parseString "__Hello world__" -- DocBold (DocString "Hello world") bold :: Parser (DocH mod Identifier) bold = DocBold . parseParagraph <$> disallowNewline ("__" *> takeUntil "__") disallowNewline :: Parser Text -> Parser Text disallowNewline = mfilter (T.all (/= '\n')) -- | Like `takeWhile`, but unconditionally take escaped characters. takeWhile_ :: (Char -> Bool) -> Parser Text takeWhile_ p = scan p_ False where p_ escaped c | escaped = Just False | not $ p c = Nothing | otherwise = Just (c == '\\') -- | Like 'takeWhile1', but unconditionally take escaped characters. takeWhile1_ :: (Char -> Bool) -> Parser Text takeWhile1_ = mfilter (not . T.null) . takeWhile_ -- | Text anchors to allow for jumping around the generated documentation. -- -- >>> parseString "#Hello world#" -- DocAName "Hello world" anchor :: Parser (DocH mod a) anchor = DocAName . T.unpack <$> disallowNewline ("#" *> takeWhile1_ (/= '#') <* "#") -- | Monospaced strings. -- -- >>> parseString "@cruel@" -- DocMonospaced (DocString "cruel") monospace :: Parser (DocH mod Identifier) monospace = DocMonospaced . parseParagraph <$> ("@" *> takeWhile1_ (/= '@') <* "@") -- | Module names. -- -- Note that we allow '#' and '\' to support anchors (old style anchors are of -- the form "SomeModule\#anchor"). moduleName :: Parser (DocH mod a) moduleName = DocModule <$> ("\"" *> modid <* "\"") where modid = intercalate "." <$> conid `Parsec.sepBy1` "." conid = (:) <$> Parsec.satisfy (\c -> isAlpha c && isUpper c) <*> many (conChar <|> Parsec.oneOf "\\#") conChar = Parsec.alphaNum <|> Parsec.char '_' -- | Picture parser, surrounded by \<\< and \>\>. It's possible to specify -- a title for the picture. -- -- >>> parseString "<<hello.png>>" -- DocPic (Picture {pictureUri = "hello.png", pictureTitle = Nothing}) -- >>> parseString "<<hello.png world>>" -- DocPic (Picture {pictureUri = "hello.png", pictureTitle = Just "world"}) picture :: Parser (DocH mod a) picture = DocPic . makeLabeled Picture <$> disallowNewline ("<<" *> takeUntil ">>") -- | Inline math parser, surrounded by \\( and \\). -- -- >>> parseString "\\(\\int_{-\\infty}^{\\infty} e^{-x^2/2} = \\sqrt{2\\pi}\\)" -- DocMathInline "\\int_{-\\infty}^{\\infty} e^{-x^2/2} = \\sqrt{2\\pi}" mathInline :: Parser (DocH mod a) mathInline = DocMathInline . T.unpack <$> disallowNewline ("\\(" *> takeUntil "\\)") -- | Display math parser, surrounded by \\[ and \\]. -- -- >>> parseString "\\[\\int_{-\\infty}^{\\infty} e^{-x^2/2} = \\sqrt{2\\pi}\\]" -- DocMathDisplay "\\int_{-\\infty}^{\\infty} e^{-x^2/2} = \\sqrt{2\\pi}" mathDisplay :: Parser (DocH mod a) mathDisplay = DocMathDisplay . T.unpack <$> ("\\[" *> takeUntil "\\]") -- | Markdown image parser. As per the commonmark reference recommendation, the -- description text for an image converted to its a plain string representation. -- -- >>> parseString "![some /emphasis/ in a description](www.site.com)" -- DocPic (Picture "www.site.com" (Just "some emphasis in a description")) markdownImage :: Parser (DocH mod Identifier) markdownImage = DocPic . fromHyperlink <$> ("!" *> linkParser) where fromHyperlink (Hyperlink u l) = Picture u (fmap (markup stringMarkup) l) stringMarkup = plainMarkup (const "") (\(l,c,r) -> [l] <> c <> [r]) -- | Paragraph parser, called by 'parseParas'. paragraph :: Parser (DocH mod Identifier) paragraph = choice' [ examples , table , do indent <- takeIndent choice' [ since , unorderedList indent , orderedList indent , birdtracks , codeblock , property , header , textParagraphThatStartsWithMarkdownLink , definitionList indent , docParagraph <$> textParagraph ] ] -- | Provides support for grid tables. -- -- Tables are composed by an optional header and body. The header is composed by -- a single row. The body is composed by a non-empty list of rows. -- -- Example table with header: -- -- > +----------+----------+ -- > | /32bit/ | 64bit | -- > +==========+==========+ -- > | 0x0000 | @0x0000@ | -- > +----------+----------+ -- -- Algorithms loosely follows ideas in -- http://docutils.sourceforge.net/docutils/parsers/rst/tableparser.py -- table :: Parser (DocH mod Identifier) table = do -- first we parse the first row, which determines the width of the table firstRow <- parseFirstRow let len = T.length firstRow -- then we parse all consequtive rows starting and ending with + or |, -- of the width `len`. restRows <- many (try (parseRestRows len)) -- Now we gathered the table block, the next step is to split the block -- into cells. DocTable <$> tableStepTwo len (firstRow : restRows) where parseFirstRow :: Parser Text parseFirstRow = do skipHorizontalSpace cs <- takeWhile (\c -> c == '-' || c == '+') -- upper-left and upper-right corners are `+` guard (T.length cs >= 2 && T.head cs == '+' && T.last cs == '+') -- trailing space skipHorizontalSpace _ <- Parsec.newline return cs parseRestRows :: Int -> Parser Text parseRestRows l = do skipHorizontalSpace bs <- scan predicate l -- Left and right edges are `|` or `+` guard (T.length bs >= 2 && (T.head bs == '|' || T.head bs == '+') && (T.last bs == '|' || T.last bs == '+')) -- trailing space skipHorizontalSpace _ <- Parsec.newline return bs where predicate n c | n <= 0 = Nothing | c == '\n' = Nothing | otherwise = Just (n - 1) -- Second step searchs for row of '+' and '=' characters, records it's index -- and changes to '=' to '-'. tableStepTwo :: Int -- ^ width -> [Text] -- ^ rows -> Parser (Table (DocH mod Identifier)) tableStepTwo width = go 0 [] where go _ left [] = tableStepThree width (reverse left) Nothing go n left (r : rs) | T.all (`elem` ['+', '=']) r = tableStepThree width (reverse left ++ r' : rs) (Just n) | otherwise = go (n + 1) (r : left) rs where r' = T.map (\c -> if c == '=' then '-' else c) r -- Third step recognises cells in the table area, returning a list of TC, cells. tableStepThree :: Int -- ^ width -> [Text] -- ^ rows -> Maybe Int -- ^ index of header separator -> Parser (Table (DocH mod Identifier)) tableStepThree width rs hdrIndex = do cells <- loop (Set.singleton (0, 0)) tableStepFour rs hdrIndex cells where height = length rs loop :: Set.Set (Int, Int) -> Parser [TC] loop queue = case Set.minView queue of Nothing -> return [] Just ((y, x), queue') | y + 1 >= height || x + 1 >= width -> loop queue' | otherwise -> case scanRight x y of Nothing -> loop queue' Just (x2, y2) -> do let tc = TC y x y2 x2 fmap (tc :) $ loop $ queue' `Set.union` Set.fromList [(y, x2), (y2, x), (y2, x2)] -- scan right looking for +, then try scan down -- -- do we need to record + saw on the way left and down? scanRight :: Int -> Int -> Maybe (Int, Int) scanRight x y = go (x + 1) where bs = rs !! y go x' | x' >= width = fail "overflow right " | T.index bs x' == '+' = scanDown x y x' <|> go (x' + 1) | T.index bs x' == '-' = go (x' + 1) | otherwise = fail $ "not a border (right) " ++ show (x,y,x') -- scan down looking for + scanDown :: Int -> Int -> Int -> Maybe (Int, Int) scanDown x y x2 = go (y + 1) where go y' | y' >= height = fail "overflow down" | T.index (rs !! y') x2 == '+' = scanLeft x y x2 y' <|> go (y' + 1) | T.index (rs !! y') x2 == '|' = go (y' + 1) | otherwise = fail $ "not a border (down) " ++ show (x,y,x2,y') -- check that at y2 x..x2 characters are '+' or '-' scanLeft :: Int -> Int -> Int -> Int -> Maybe (Int, Int) scanLeft x y x2 y2 | all (\x' -> T.index bs x' `elem` ['+', '-']) [x..x2] = scanUp x y x2 y2 | otherwise = fail $ "not a border (left) " ++ show (x,y,x2,y2) where bs = rs !! y2 -- check that at y2 x..x2 characters are '+' or '-' scanUp :: Int -> Int -> Int -> Int -> Maybe (Int, Int) scanUp x y x2 y2 | all (\y' -> T.index (rs !! y') x `elem` ['+', '|']) [y..y2] = return (x2, y2) | otherwise = fail $ "not a border (up) " ++ show (x,y,x2,y2) -- | table cell: top left bottom right data TC = TC !Int !Int !Int !Int deriving Show tcXS :: TC -> [Int] tcXS (TC _ x _ x2) = [x, x2] tcYS :: TC -> [Int] tcYS (TC y _ y2 _) = [y, y2] -- | Fourth step. Given the locations of cells, forms 'Table' structure. tableStepFour :: [Text] -> Maybe Int -> [TC] -> Parser (Table (DocH mod Identifier)) tableStepFour rs hdrIndex cells = case hdrIndex of Nothing -> return $ Table [] rowsDoc Just i -> case elemIndex i yTabStops of Nothing -> return $ Table [] rowsDoc Just i' -> return $ uncurry Table $ splitAt i' rowsDoc where xTabStops = sortNub $ concatMap tcXS cells yTabStops = sortNub $ concatMap tcYS cells sortNub :: Ord a => [a] -> [a] sortNub = Set.toList . Set.fromList init' :: [a] -> [a] init' [] = [] init' [_] = [] init' (x : xs) = x : init' xs rowsDoc = (fmap . fmap) parseParagraph rows rows = map makeRow (init' yTabStops) where makeRow y = TableRow $ mapMaybe (makeCell y) cells makeCell y (TC y' x y2 x2) | y /= y' = Nothing | otherwise = Just $ TableCell xts yts (extract (x + 1) (y + 1) (x2 - 1) (y2 - 1)) where xts = length $ P.takeWhile (< x2) $ dropWhile (< x) xTabStops yts = length $ P.takeWhile (< y2) $ dropWhile (< y) yTabStops -- extract cell contents given boundaries extract :: Int -> Int -> Int -> Int -> Text extract x y x2 y2 = T.intercalate "\n" [ T.take (x2 - x + 1) $ T.drop x $ rs !! y' | y' <- [y .. y2] ] -- | Parse \@since annotations. since :: Parser (DocH mod a) since = ("@since " *> version <* skipHorizontalSpace <* endOfLine) >>= setSince >> return DocEmpty where version = decimal `Parsec.sepBy1` "." -- | Headers inside the comment denoted with @=@ signs, up to 6 levels -- deep. -- -- >>> snd <$> parseOnly header "= Hello" -- Right (DocHeader (Header {headerLevel = 1, headerTitle = DocString "Hello"})) -- >>> snd <$> parseOnly header "== World" -- Right (DocHeader (Header {headerLevel = 2, headerTitle = DocString "World"})) header :: Parser (DocH mod Identifier) header = do let psers = map (string . flip T.replicate "=") [6, 5 .. 1] pser = choice' psers delim <- T.unpack <$> pser line <- skipHorizontalSpace *> nonEmptyLine >>= return . parseText rest <- try paragraph <|> return DocEmpty return $ DocHeader (Header (length delim) line) `docAppend` rest textParagraph :: Parser (DocH mod Identifier) textParagraph = parseText . T.intercalate "\n" <$> some nonEmptyLine textParagraphThatStartsWithMarkdownLink :: Parser (DocH mod Identifier) textParagraphThatStartsWithMarkdownLink = docParagraph <$> (docAppend <$> markdownLink <*> optionalTextParagraph) where optionalTextParagraph :: Parser (DocH mod Identifier) optionalTextParagraph = choice' [ docAppend <$> whitespace <*> textParagraph , pure DocEmpty ] whitespace :: Parser (DocH mod a) whitespace = DocString <$> (f <$> takeHorizontalSpace <*> optional "\n") where f :: Text -> Maybe Text -> String f xs (fromMaybe "" -> x) | T.null (xs <> x) = "" | otherwise = " " -- | Parses unordered (bullet) lists. unorderedList :: Text -> Parser (DocH mod Identifier) unorderedList indent = DocUnorderedList <$> p where p = ("*" <|> "-") *> innerList indent p -- | Parses ordered lists (numbered or dashed). orderedList :: Text -> Parser (DocH mod Identifier) orderedList indent = DocOrderedList <$> p where p = (paren <|> dot) *> innerList indent p dot = (decimal :: Parser Int) <* "." paren = "(" *> decimal <* ")" -- | Generic function collecting any further lines belonging to the -- list entry and recursively collecting any further lists in the -- same paragraph. Usually used as -- -- > someListFunction = listBeginning *> innerList someListFunction innerList :: Text -> Parser [DocH mod Identifier] -> Parser [DocH mod Identifier] innerList indent item = do c <- takeLine (cs, items) <- more indent item let contents = docParagraph . parseText . dropNLs . T.unlines $ c : cs return $ case items of Left p -> [contents `docAppend` p] Right i -> contents : i -- | Parses definition lists. definitionList :: Text -> Parser (DocH mod Identifier) definitionList indent = DocDefList <$> p where p = do label <- "[" *> (parseParagraph <$> takeWhile1_ (`notElem` ("]\n" :: String))) <* ("]" <* optional ":") c <- takeLine (cs, items) <- more indent p let contents = parseText . dropNLs . T.unlines $ c : cs return $ case items of Left x -> [(label, contents `docAppend` x)] Right i -> (label, contents) : i -- | Drops all trailing newlines. dropNLs :: Text -> Text dropNLs = T.dropWhileEnd (== '\n') -- | Main worker for 'innerList' and 'definitionList'. -- We need the 'Either' here to be able to tell in the respective functions -- whether we're dealing with the next list or a nested paragraph. more :: Monoid a => Text -> Parser a -> Parser ([Text], Either (DocH mod Identifier) a) more indent item = choice' [ innerParagraphs indent , moreListItems indent item , moreContent indent item , pure ([], Right mempty) ] -- | Used by 'innerList' and 'definitionList' to parse any nested paragraphs. innerParagraphs :: Text -> Parser ([Text], Either (DocH mod Identifier) a) innerParagraphs indent = (,) [] . Left <$> ("\n" *> indentedParagraphs indent) -- | Attempts to fetch the next list if possibly. Used by 'innerList' and -- 'definitionList' to recursively grab lists that aren't separated by a whole -- paragraph. moreListItems :: Text -> Parser a -> Parser ([Text], Either (DocH mod Identifier) a) moreListItems indent item = (,) [] . Right <$> indentedItem where indentedItem = string indent *> Parsec.spaces *> item -- | Helper for 'innerList' and 'definitionList' which simply takes -- a line of text and attempts to parse more list content with 'more'. moreContent :: Monoid a => Text -> Parser a -> Parser ([Text], Either (DocH mod Identifier) a) moreContent indent item = first . (:) <$> nonEmptyLine <*> more indent item -- | Parses an indented paragraph. -- The indentation is 4 spaces. indentedParagraphs :: Text -> Parser (DocH mod Identifier) indentedParagraphs indent = (T.unpack . T.concat <$> dropFrontOfPara indent') >>= parseParagraphs where indent' = string $ indent <> " " -- | Grab as many fully indented paragraphs as we can. dropFrontOfPara :: Parser Text -> Parser [Text] dropFrontOfPara sp = do currentParagraph <- some (try (sp *> takeNonEmptyLine)) followingParagraphs <- choice' [ skipHorizontalSpace *> nextPar -- we have more paragraphs to take , skipHorizontalSpace *> nlList -- end of the ride, remember the newline , Parsec.eof *> return [] -- nothing more to take at all ] return (currentParagraph ++ followingParagraphs) where nextPar = (++) <$> nlList <*> dropFrontOfPara sp nlList = "\n" *> return ["\n"] nonSpace :: Text -> Parser Text nonSpace xs | T.all isSpace xs = fail "empty line" | otherwise = return xs -- | Takes a non-empty, not fully whitespace line. -- -- Doesn't discard the trailing newline. takeNonEmptyLine :: Parser Text takeNonEmptyLine = do l <- takeWhile1 (/= '\n') >>= nonSpace _ <- "\n" pure (l <> "\n") -- | Takes indentation of first non-empty line. -- -- More precisely: skips all whitespace-only lines and returns indentation -- (horizontal space, might be empty) of that non-empty line. takeIndent :: Parser Text takeIndent = do indent <- takeHorizontalSpace choice' [ "\n" *> takeIndent , return indent ] -- | Blocks of text of the form: -- -- >> foo -- >> bar -- >> baz -- birdtracks :: Parser (DocH mod a) birdtracks = DocCodeBlock . DocString . T.unpack . T.intercalate "\n" . stripSpace <$> some line where line = try (skipHorizontalSpace *> ">" *> takeLine) stripSpace :: [Text] -> [Text] stripSpace = fromMaybe <*> mapM strip' where strip' t = case T.uncons t of Nothing -> Just "" Just (' ',t') -> Just t' _ -> Nothing -- | Parses examples. Examples are a paragraph level entitity (separated by an empty line). -- Consecutive examples are accepted. examples :: Parser (DocH mod a) examples = DocExamples <$> (many (try (skipHorizontalSpace *> "\n")) *> go) where go :: Parser [Example] go = do prefix <- takeHorizontalSpace <* ">>>" expr <- takeLine (rs, es) <- resultAndMoreExamples return (makeExample prefix expr rs : es) where resultAndMoreExamples :: Parser ([Text], [Example]) resultAndMoreExamples = choice' [ moreExamples, result, pure ([], []) ] where moreExamples :: Parser ([Text], [Example]) moreExamples = (,) [] <$> go result :: Parser ([Text], [Example]) result = first . (:) <$> nonEmptyLine <*> resultAndMoreExamples makeExample :: Text -> Text -> [Text] -> Example makeExample prefix expression res = Example (T.unpack (T.strip expression)) result where result = map (T.unpack . substituteBlankLine . tryStripPrefix) res tryStripPrefix xs = fromMaybe xs (T.stripPrefix prefix xs) substituteBlankLine "<BLANKLINE>" = "" substituteBlankLine xs = xs nonEmptyLine :: Parser Text nonEmptyLine = try (mfilter (T.any (not . isSpace)) takeLine) takeLine :: Parser Text takeLine = try (takeWhile (/= '\n') <* endOfLine) endOfLine :: Parser () endOfLine = void "\n" <|> Parsec.eof -- | Property parser. -- -- >>> snd <$> parseOnly property "prop> hello world" -- Right (DocProperty "hello world") property :: Parser (DocH mod a) property = DocProperty . T.unpack . T.strip <$> ("prop>" *> takeWhile1 (/= '\n')) -- | -- Paragraph level codeblock. Anything between the two delimiting \@ is parsed -- for markup. codeblock :: Parser (DocH mod Identifier) codeblock = DocCodeBlock . parseParagraph . dropSpaces <$> ("@" *> skipHorizontalSpace *> "\n" *> block' <* "@") where dropSpaces xs = case splitByNl xs of [] -> xs ys -> case T.uncons (last ys) of Just (' ',_) -> case mapM dropSpace ys of Nothing -> xs Just zs -> T.intercalate "\n" zs _ -> xs -- This is necessary because ‘lines’ swallows up a trailing newline -- and we lose information about whether the last line belongs to @ or to -- text which we need to decide whether we actually want to be dropping -- anything at all. splitByNl = unfoldr (\x -> case T.uncons x of Just ('\n',x') -> Just (T.span (/= '\n') x') _ -> Nothing) . ("\n" <>) dropSpace t = case T.uncons t of Nothing -> Just "" Just (' ',t') -> Just t' _ -> Nothing block' = scan p False where p isNewline c | isNewline && c == '@' = Nothing | isNewline && isSpace c = Just isNewline | otherwise = Just $ c == '\n' hyperlink :: Parser (DocH mod Identifier) hyperlink = choice' [ angleBracketLink, markdownLink, autoUrl ] angleBracketLink :: Parser (DocH mod a) angleBracketLink = DocHyperlink . makeLabeled (\s -> Hyperlink s . fmap DocString) <$> disallowNewline ("<" *> takeUntil ">") markdownLink :: Parser (DocH mod Identifier) markdownLink = DocHyperlink <$> linkParser linkParser :: Parser (Hyperlink (DocH mod Identifier)) linkParser = flip Hyperlink <$> label <*> (whitespace *> url) where label :: Parser (Maybe (DocH mod Identifier)) label = Just . parseParagraph . T.strip <$> ("[" *> takeUntil "]") whitespace :: Parser () whitespace = skipHorizontalSpace <* optional ("\n" *> skipHorizontalSpace) url :: Parser String url = rejectWhitespace (decode <$> ("(" *> takeUntil ")")) rejectWhitespace :: MonadPlus m => m String -> m String rejectWhitespace = mfilter (all (not . isSpace)) decode :: Text -> String decode = T.unpack . removeEscapes -- | Looks for URL-like things to automatically hyperlink even if they -- weren't marked as links. autoUrl :: Parser (DocH mod a) autoUrl = mkLink <$> url where url = mappend <$> choice' [ "http://", "https://", "ftp://"] <*> takeWhile1 (not . isSpace) mkLink :: Text -> DocH mod a mkLink s = case T.unsnoc s of Just (xs,x) | x `elem` (",.!?" :: String) -> DocHyperlink (mkHyperlink xs) `docAppend` DocString [x] _ -> DocHyperlink (mkHyperlink s) mkHyperlink :: Text -> Hyperlink (DocH mod a) mkHyperlink lnk = Hyperlink (T.unpack lnk) Nothing -- | Parses strings between identifier delimiters. Consumes all input that it -- deems to be valid in an identifier. Note that it simply blindly consumes -- characters and does no actual validation itself. parseValid :: Parser String parseValid = p some where idChar = Parsec.satisfy (\c -> isAlphaNum c || isSymbolChar c || c == '_') p p' = do vs <- p' idChar c <- peekChar' case c of '`' -> return vs '\'' -> choice' [ (\x -> vs ++ "'" ++ x) <$> ("'" *> p many), return vs ] _ -> fail "outofvalid" -- | Parses identifiers with help of 'parseValid'. Asks GHC for -- 'String' from the string it deems valid. identifier :: Parser (DocH mod Identifier) identifier = do o <- idDelim vid <- parseValid e <- idDelim return $ DocIdentifier (o, vid, e) where idDelim = Parsec.satisfy (\c -> c == '\'' || c == '`')