{-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE StandaloneDeriving #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE UndecidableInstances #-} {-# LANGUAGE IncoherentInstances #-} -- | -- 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' . 'parseParas'@ module Documentation.Haddock.Parser ( parseString, parseParas , overIdentifier, toRegular, Identifier ) where import Control.Applicative import Control.Arrow (first) import Control.Monad (void, mfilter) import Data.Attoparsec.ByteString.Char8 hiding (parse, take, endOfLine) import qualified Data.ByteString.Char8 as BS import Data.Char (chr, isAsciiUpper) import Data.List (stripPrefix, intercalate, unfoldr) import Data.Maybe (fromMaybe) import Data.Monoid import Documentation.Haddock.Doc import Documentation.Haddock.Parser.Util import Documentation.Haddock.Types import Documentation.Haddock.Utf8 import Prelude hiding (takeWhile) -- $setup -- >>> :set -XOverloadedStrings -- | 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 x) = DocHyperlink x g (DocPic x) = DocPic 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 parse :: Parser a -> BS.ByteString -> a parse p = either err id . parseOnly (p <* endOfInput) where err = error . ("Haddock.Parser.parse: " ++) -- | Main entry point to the parser. Appends the newline character -- to the input string. parseParas :: String -- ^ String to parse -> DocH mod Identifier parseParas = parse (p <* skipSpace) . encodeUtf8 . (++ "\n") where p :: Parser (DocH mod Identifier) p = docConcat <$> paragraph `sepBy` many (skipHorizontalSpace *> "\n") -- | Parse a text paragraph. Actually just a wrapper over 'parseStringBS' which -- drops leading whitespace and encodes the string to UTF8 first. parseString :: String -> DocH mod Identifier parseString = parseStringBS . encodeUtf8 . dropWhile isSpace parseStringBS :: BS.ByteString -> DocH mod Identifier parseStringBS = parse p where p :: Parser (DocH mod Identifier) p = docConcat <$> many (monospace <|> anchor <|> identifier <|> moduleName <|> picture <|> hyperlink <|> bold <|> emphasis <|> encodedChar <|> string' <|> skipSpecialChar) -- | Parses and processes -- <https://en.wikipedia.org/wiki/Numeric_character_reference Numeric character references> -- -- >>> parseOnly encodedChar "A" -- Right (DocString "A") encodedChar :: Parser (DocH mod a) encodedChar = "&#" *> c <* ";" where c = DocString . return . chr <$> num num = hex <|> decimal hex = ("x" <|> "X") *> hexadecimal -- | List of characters that we use to delimit any special markup. -- Once we have checked for any of these and tried to parse the -- relevant markup, we can assume they are used as regular text. specialChar :: [Char] specialChar = "_/<@\"&'`# " -- | Plain, regular parser for text. Called as one of the last parsers -- to ensure that we have already given a chance to more meaningful parsers -- before capturing their characers. string' :: Parser (DocH mod a) string' = DocString . unescape . decodeUtf8 <$> 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 <$> satisfy (`elem` specialChar) -- | Emphasis parser. -- -- >>> parseOnly emphasis "/Hello world/" -- Right (DocEmphasis (DocString "Hello world")) emphasis :: Parser (DocH mod Identifier) emphasis = DocEmphasis . parseStringBS <$> mfilter ('\n' `BS.notElem`) ("/" *> takeWhile1_ (/= '/') <* "/") -- | Bold parser. -- -- >>> parseOnly bold "__Hello world__" -- Right (DocBold (DocString "Hello world")) bold :: Parser (DocH mod Identifier) bold = DocBold . parseStringBS <$> disallowNewline ("__" *> takeUntil "__") disallowNewline :: Parser BS.ByteString -> Parser BS.ByteString disallowNewline = mfilter ('\n' `BS.notElem`) -- | Like `takeWhile`, but unconditionally take escaped characters. takeWhile_ :: (Char -> Bool) -> Parser BS.ByteString takeWhile_ p = scan False p_ 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 BS.ByteString takeWhile1_ = mfilter (not . BS.null) . takeWhile_ -- | Text anchors to allow for jumping around the generated documentation. -- -- >>> parseOnly anchor "#Hello world#" -- Right (DocAName "Hello world") anchor :: Parser (DocH mod a) anchor = DocAName . decodeUtf8 <$> disallowNewline ("#" *> takeWhile1_ (/= '#') <* "#") -- | Monospaced strings. -- -- >>> parseOnly monospace "@cruel@" -- Right (DocMonospaced (DocString "cruel")) monospace :: Parser (DocH mod Identifier) monospace = DocMonospaced . parseStringBS <$> ("@" *> takeWhile1_ (/= '@') <* "@") moduleName :: Parser (DocH mod a) moduleName = DocModule <$> (char '"' *> modid <* char '"') where modid = intercalate "." <$> conid `sepBy1` "." conid = (:) <$> satisfy isAsciiUpper -- NOTE: According to Haskell 2010 we should actually only -- accept {small | large | digit | ' } here. But as we can't -- match on unicode characters, this is currently not possible. -- Note that we allow ‘#’ to suport anchors. <*> (decodeUtf8 <$> takeWhile (`notElem` " .&[{}(=*)+]!|@/;,^?\"\n")) -- | Picture parser, surrounded by \<\< and \>\>. It's possible to specify -- a title for the picture. -- -- >>> parseOnly picture "<<hello.png>>" -- Right (DocPic (Picture {pictureUri = "hello.png", pictureTitle = Nothing})) -- >>> parseOnly picture "<<hello.png world>>" -- Right (DocPic (Picture {pictureUri = "hello.png", pictureTitle = Just "world"})) picture :: Parser (DocH mod a) picture = DocPic . makeLabeled Picture . decodeUtf8 <$> disallowNewline ("<<" *> takeUntil ">>") -- | Paragraph parser, called by 'parseParas'. paragraph :: Parser (DocH mod Identifier) paragraph = examples <|> skipSpace *> (list <|> birdtracks <|> codeblock <|> property <|> header <|> textParagraph) -- | Headers inside the comment denoted with @=@ signs, up to 6 levels -- deep. -- -- >>> parseOnly header "= Hello" -- Right (DocHeader (Header {headerLevel = 1, headerTitle = DocString "Hello"})) -- >>> parseOnly header "== World" -- Right (DocHeader (Header {headerLevel = 2, headerTitle = DocString "World"})) header :: Parser (DocH mod Identifier) header = do let psers = map (string . encodeUtf8 . concat . flip replicate "=") [6, 5 .. 1] pser = foldl1 (<|>) psers delim <- decodeUtf8 <$> pser line <- skipHorizontalSpace *> nonEmptyLine >>= return . parseString rest <- paragraph <|> return DocEmpty return $ DocHeader (Header (length delim) line) `docAppend` rest textParagraph :: Parser (DocH mod Identifier) textParagraph = docParagraph . parseString . intercalate "\n" <$> many1 nonEmptyLine -- | List parser, called by 'paragraph'. list :: Parser (DocH mod Identifier) list = DocUnorderedList <$> unorderedList <|> DocOrderedList <$> orderedList <|> DocDefList <$> definitionList -- | Parses unordered (bullet) lists. unorderedList :: Parser [DocH mod Identifier] unorderedList = ("*" <|> "-") *> innerList unorderedList -- | Parses ordered lists (numbered or dashed). orderedList :: Parser [DocH mod Identifier] orderedList = (paren <|> dot) *> innerList orderedList where 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 :: Parser [DocH mod Identifier] -> Parser [DocH mod Identifier] innerList item = do c <- takeLine (cs, items) <- more item let contents = docParagraph . parseString . dropNLs . unlines $ c : cs return $ case items of Left p -> [contents `docAppend` p] Right i -> contents : i -- | Parses definition lists. definitionList :: Parser [(DocH mod Identifier, DocH mod Identifier)] definitionList = do label <- "[" *> (parseStringBS <$> takeWhile1 (`notElem` "]\n")) <* "]" c <- takeLine (cs, items) <- more definitionList let contents = parseString . dropNLs . unlines $ c : cs return $ case items of Left p -> [(label, contents `docAppend` p)] Right i -> (label, contents) : i -- | Drops all trailing newlines. dropNLs :: String -> String dropNLs = reverse . dropWhile (== '\n') . reverse -- | 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 => Parser a -> Parser ([String], Either (DocH mod Identifier) a) more item = innerParagraphs <|> moreListItems item <|> moreContent item <|> pure ([], Right mempty) -- | Used by 'innerList' and 'definitionList' to parse any nested paragraphs. innerParagraphs :: Parser ([String], Either (DocH mod Identifier) a) innerParagraphs = (,) [] . Left <$> ("\n" *> indentedParagraphs) -- | Attempts to fetch the next list if possibly. Used by 'innerList' and -- 'definitionList' to recursively grab lists that aren't separated by a whole -- paragraph. moreListItems :: Parser a -> Parser ([String], Either (DocH mod Identifier) a) moreListItems item = (,) [] . Right <$> (skipSpace *> 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 => Parser a -> Parser ([String], Either (DocH mod Identifier) a) moreContent item = first . (:) <$> nonEmptyLine <*> more item -- | Runs the 'parseParas' parser on an indented paragraph. -- The indentation is 4 spaces. indentedParagraphs :: Parser (DocH mod Identifier) indentedParagraphs = parseParas . concat <$> dropFrontOfPara " " -- | Grab as many fully indented paragraphs as we can. dropFrontOfPara :: Parser BS.ByteString -> Parser [String] dropFrontOfPara sp = do currentParagraph <- some (sp *> takeNonEmptyLine) followingParagraphs <- skipHorizontalSpace *> nextPar -- we have more paragraphs to take <|> skipHorizontalSpace *> nlList -- end of the ride, remember the newline <|> endOfInput *> return [] -- nothing more to take at all return (currentParagraph ++ followingParagraphs) where nextPar = (++) <$> nlList <*> dropFrontOfPara sp nlList = "\n" *> return ["\n"] nonSpace :: BS.ByteString -> Parser BS.ByteString nonSpace xs | not $ any (not . isSpace) $ decodeUtf8 xs = fail "empty line" | otherwise = return xs -- | Takes a non-empty, not fully whitespace line. -- -- Doesn't discard the trailing newline. takeNonEmptyLine :: Parser String takeNonEmptyLine = do (++ "\n") . decodeUtf8 <$> (takeWhile1 (/= '\n') >>= nonSpace) <* "\n" -- | Blocks of text of the form: -- -- >> foo -- >> bar -- >> baz -- birdtracks :: Parser (DocH mod a) birdtracks = DocCodeBlock . DocString . intercalate "\n" . stripSpace <$> many1 line where line = skipHorizontalSpace *> ">" *> takeLine stripSpace :: [String] -> [String] stripSpace = fromMaybe <*> mapM strip' where strip' (' ':xs') = Just xs' strip' "" = Just "" strip' _ = 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 <$> (many (skipHorizontalSpace *> "\n") *> go) where go :: Parser [Example] go = do prefix <- decodeUtf8 <$> takeHorizontalSpace <* ">>>" expr <- takeLine (rs, es) <- resultAndMoreExamples return (makeExample prefix expr rs : es) where resultAndMoreExamples :: Parser ([String], [Example]) resultAndMoreExamples = moreExamples <|> result <|> pure ([], []) where moreExamples :: Parser ([String], [Example]) moreExamples = (,) [] <$> go result :: Parser ([String], [Example]) result = first . (:) <$> nonEmptyLine <*> resultAndMoreExamples makeExample :: String -> String -> [String] -> Example makeExample prefix expression res = Example (strip expression) result where result = map (substituteBlankLine . tryStripPrefix) res tryStripPrefix xs = fromMaybe xs (stripPrefix prefix xs) substituteBlankLine "<BLANKLINE>" = "" substituteBlankLine xs = xs nonEmptyLine :: Parser String nonEmptyLine = mfilter (any (not . isSpace)) takeLine takeLine :: Parser String takeLine = decodeUtf8 <$> takeWhile (/= '\n') <* endOfLine endOfLine :: Parser () endOfLine = void "\n" <|> endOfInput -- | Property parser. -- -- >>> parseOnly property "prop> hello world" -- Right (DocProperty "hello world") property :: Parser (DocH mod a) property = DocProperty . strip . decodeUtf8 <$> ("prop>" *> takeWhile1 (/= '\n')) -- | -- Paragraph level codeblock. Anything between the two delimiting \@ is parsed -- for markup. codeblock :: Parser (DocH mod Identifier) codeblock = DocCodeBlock . parseStringBS . dropSpaces <$> ("@" *> skipHorizontalSpace *> "\n" *> block' <* "@") where dropSpaces xs = let rs = decodeUtf8 xs in case splitByNl rs of [] -> xs ys -> case last ys of ' ':_ -> case mapM dropSpace ys of Nothing -> xs Just zs -> encodeUtf8 $ 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 x of '\n':s -> Just (span (/= '\n') s) _ -> Nothing) . ('\n' :) dropSpace "" = Just "" dropSpace (' ':xs) = Just xs dropSpace _ = Nothing block' = scan False p where p isNewline c | isNewline && c == '@' = Nothing | isNewline && isSpace c = Just isNewline | otherwise = Just $ c == '\n' -- | Parses links that were specifically marked as such. hyperlink :: Parser (DocH mod a) hyperlink = DocHyperlink . makeLabeled Hyperlink . decodeUtf8 <$> disallowNewline ("<" *> takeUntil ">") <|> autoUrl -- | Looks for URL-like things to automatically hyperlink even if they -- weren't marked as links. autoUrl :: Parser (DocH mod a) autoUrl = mkLink <$> url where url = mappend <$> ("http://" <|> "https://" <|> "ftp://") <*> takeWhile1 (not . isSpace) mkLink :: BS.ByteString -> DocH mod a mkLink s = case unsnoc s of Just (xs, x) | x `elem` ",.!?" -> DocHyperlink (Hyperlink (decodeUtf8 xs) Nothing) `docAppend` DocString [x] _ -> DocHyperlink (Hyperlink (decodeUtf8 s) 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 = do vs' <- many' $ utf8String "⋆" <|> return <$> idChar let vs = concat vs' c <- peekChar case c of Just '`' -> return vs Just '\'' -> (\x -> vs ++ "'" ++ x) <$> ("'" *> parseValid) <|> return vs _ -> fail "outofvalid" where idChar = satisfy (`elem` "_.!#$%&*+/<=>?@\\|-~:^") <|> digit <|> letter_ascii -- | Parses UTF8 strings from ByteString streams. utf8String :: String -> Parser String utf8String x = decodeUtf8 <$> string (encodeUtf8 x) -- | 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 = char '\'' <|> char '`'