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|
{-# LANGUAGE OverloadedStrings #-}
{- |
Module : Text.Pandoc.Readers.HTML.Parsing
Copyright : Copyright (C) 2006-2020 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Parsing functions and utilities.
-}
module Text.Pandoc.Readers.HTML.Parsing
( pInTags
, pInTags'
, pInTag
, pAny
, pCloses
, pSatisfy
, pBlank
, matchTagClose
, matchTagOpen
, isSpace
)
where
import Control.Monad (guard, void, mzero)
import Data.Text (Text)
import Text.HTML.TagSoup
import Text.Pandoc.Class.PandocMonad (PandocMonad (..))
import Text.Pandoc.Parsing
( (<|>), eof, getPosition, lookAhead, manyTill, newPos, optional
, skipMany, setPosition, token, try)
import Text.Pandoc.Readers.HTML.TagCategories
import Text.Pandoc.Readers.HTML.Types
import Text.Pandoc.Shared (tshow)
import qualified Data.Set as Set
import qualified Data.Text as T
pInTags :: (PandocMonad m, Monoid a) => Text -> TagParser m a -> TagParser m a
pInTags tagtype parser = pInTags' tagtype (const True) parser
pInTags' :: (PandocMonad m, Monoid a)
=> Text
-> (Tag Text -> Bool)
-> TagParser m a
-> TagParser m a
pInTags' tagtype tagtest parser = try $ do
pSatisfy (\t -> t ~== TagOpen tagtype [] && tagtest t)
mconcat <$> manyTill parser (pCloses tagtype <|> eof)
-- parses p, preceded by an opening tag (optional if tagsOptional)
-- and followed by a closing tag (optional if tagsOptional)
pInTag :: PandocMonad m => Bool -> Text -> TagParser m a -> TagParser m a
pInTag tagsOptional tagtype p = try $ do
skipMany pBlank
(if tagsOptional then optional else void) $ pSatisfy (matchTagOpen tagtype [])
skipMany pBlank
x <- p
skipMany pBlank
(if tagsOptional then optional else void) $ pSatisfy (matchTagClose tagtype)
skipMany pBlank
return x
pCloses :: PandocMonad m => Text -> TagParser m ()
pCloses tagtype = try $ do
t <- lookAhead $ pSatisfy $ \tag -> isTagClose tag || isTagOpen tag
case t of
(TagClose t') | t' == tagtype -> void pAny
(TagOpen t' _) | t' `closes` tagtype -> return ()
(TagClose "ul") | tagtype == "li" -> return ()
(TagClose "ol") | tagtype == "li" -> return ()
(TagClose "dl") | tagtype == "dd" -> return ()
(TagClose "table") | tagtype == "td" -> return ()
(TagClose "table") | tagtype == "th" -> return ()
(TagClose "table") | tagtype == "tr" -> return ()
(TagClose "td") | tagtype `Set.member` blockHtmlTags -> return ()
(TagClose "th") | tagtype `Set.member` blockHtmlTags -> return ()
(TagClose t') | tagtype == "p" && t' `Set.member` blockHtmlTags
-> return () -- see #3794
_ -> mzero
pBlank :: PandocMonad m => TagParser m ()
pBlank = try $ do
(TagText str) <- pSatisfy isTagText
guard $ T.all isSpace str
pLocation :: PandocMonad m => TagParser m ()
pLocation = do
(TagPosition r c) <- pSat isTagPosition
setPosition $ newPos "input" r c
pSat :: PandocMonad m => (Tag Text -> Bool) -> TagParser m (Tag Text)
pSat f = do
pos <- getPosition
token tshow (const pos) (\x -> if f x then Just x else Nothing)
pSatisfy :: PandocMonad m => (Tag Text -> Bool) -> TagParser m (Tag Text)
pSatisfy f = try $ optional pLocation >> pSat f
matchTagClose :: Text -> (Tag Text -> Bool)
matchTagClose t = (~== TagClose t)
matchTagOpen :: Text -> [(Text, Text)] -> (Tag Text -> Bool)
matchTagOpen t as = (~== TagOpen t as)
pAny :: PandocMonad m => TagParser m (Tag Text)
pAny = pSatisfy (const True)
isSpace :: Char -> Bool
isSpace ' ' = True
isSpace '\t' = True
isSpace '\n' = True
isSpace '\r' = True
isSpace _ = False
-- taken from HXT and extended
-- See http://www.w3.org/TR/html5/syntax.html sec 8.1.2.4 optional tags
closes :: Text -> Text -> Bool
_ `closes` "body" = False
_ `closes` "html" = False
"body" `closes` "head" = True
"a" `closes` "a" = True
"li" `closes` "li" = True
"th" `closes` t | t `elem` ["th","td"] = True
"td" `closes` t | t `elem` ["th","td"] = True
"tr" `closes` t | t `elem` ["th","td","tr"] = True
"dd" `closes` t | t `elem` ["dt", "dd"] = True
"dt" `closes` t | t `elem` ["dt","dd"] = True
"rt" `closes` t | t `elem` ["rb", "rt", "rtc"] = True
"optgroup" `closes` "optgroup" = True
"optgroup" `closes` "option" = True
"option" `closes` "option" = True
-- https://html.spec.whatwg.org/multipage/syntax.html#optional-tags
x `closes` "p" | x `elem` ["address", "article", "aside", "blockquote",
"dir", "div", "dl", "fieldset", "footer", "form", "h1", "h2", "h3", "h4",
"h5", "h6", "header", "hr", "main", "menu", "nav", "ol", "p", "pre", "section",
"table", "ul"] = True
_ `closes` "meta" = True
"form" `closes` "form" = True
"label" `closes` "label" = True
"map" `closes` "map" = True
"object" `closes` "object" = True
_ `closes` t | t `elem` ["option","style","script","textarea","title"] = True
t `closes` "select" | t /= "option" = True
"thead" `closes` "colgroup" = True
"tfoot" `closes` t | t `elem` ["thead","colgroup"] = True
"tbody" `closes` t | t `elem` ["tbody","tfoot","thead","colgroup"] = True
t `closes` t2 |
t `elem` ["h1","h2","h3","h4","h5","h6","dl","ol","ul","table","div","main","p"] &&
t2 `elem` ["h1","h2","h3","h4","h5","h6","p" ] = True -- not "div" or "main"
t1 `closes` t2 |
t1 `Set.member` blockTags &&
t2 `Set.notMember` blockTags &&
t2 `Set.notMember` eitherBlockOrInline = True
_ `closes` _ = False
|
