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Perf only change: * use 'getParserState'/'setParserState' to make 'Text'-optimized parser combinators * minimize uses of 'Data.Text.{pack,unpack,cons,snoc}'Alec Theriault authoredPerf only change: * use 'getParserState'/'setParserState' to make 'Text'-optimized parser combinators * minimize uses of 'Data.Text.{pack,unpack,cons,snoc}'
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Parser.hs 30.17 KiB
{-# 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, notElem)
import Data.Maybe (fromMaybe, mapMaybe)
import Data.Monoid
import qualified Data.Set as Set
import Documentation.Haddock.Doc
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 x) = DocHyperlink 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 "\\]")
markdownImage :: Parser (DocH mod a)
markdownImage = fromHyperlink <$> ("!" *> linkParser)
where
fromHyperlink (Hyperlink url label) = DocPic (Picture url label)
-- | Paragraph parser, called by 'parseParas'.
paragraph :: Parser (DocH mod Identifier)
paragraph = choice' [ examples
, table
, do indent <- takeIndent
choice' [ since
, unorderedList indent
, orderedList indent
, birdtracks
, codeblock
, property
, header
, textParagraphThatStartsWithMarkdownLink
, definitionList indent
, docParagraph <$> 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 a)
hyperlink = choice' [ angleBracketLink, markdownLink, autoUrl ]
angleBracketLink :: Parser (DocH mod a)
angleBracketLink =
DocHyperlink . makeLabeled Hyperlink
<$> disallowNewline ("<" *> takeUntil ">")
markdownLink :: Parser (DocH mod a)
markdownLink = DocHyperlink <$> linkParser
linkParser :: Parser Hyperlink
linkParser = flip Hyperlink <$> label <*> (whitespace *> url)
where
label :: Parser (Maybe String)
label = Just . decode . T.strip <$> ("[" *> 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 <$> choice' [ "http://", "https://", "ftp://"] <*> takeWhile1 (not . isSpace)
mkLink :: Text -> DocH mod a
mkLink s = case T.unsnoc s of
Just (xs,x) | x `elem` (",.!?" :: String) -> DocHyperlink (mkHyperlink xs) `docAppend` DocString [x]
_ -> DocHyperlink (mkHyperlink s)
mkHyperlink :: Text -> Hyperlink
mkHyperlink lnk = Hyperlink (T.unpack lnk) Nothing
-- | Parses strings between identifier delimiters. Consumes all input that it
-- deems to be valid in an identifier. Note that it simply blindly consumes
-- characters and does no actual validation itself.
parseValid :: Parser String
parseValid = p some
where
idChar = Parsec.satisfy (\c -> isAlphaNum c || isSymbolChar c || c == '_')
p p' = do
vs <- p' idChar
c <- peekChar'
case c of
'`' -> return vs
'\'' -> choice' [ (\x -> vs ++ "'" ++ x) <$> ("'" *> 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 == '`')