{-# LANGUAGE NoImplicitPrelude #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE ViewPatterns #-} {- | Module : Text.Pandoc.Readers.HTML Copyright : Copyright (C) 2006-2019 John MacFarlane License : GNU GPL, version 2 or above Maintainer : John MacFarlane Stability : alpha Portability : portable Conversion of HTML to 'Pandoc' document. -} module Text.Pandoc.Readers.HTML ( readHtml , htmlTag , htmlInBalanced , isInlineTag , isBlockTag , NamedTag(..) , isTextTag , isCommentTag ) where import Prelude import Control.Applicative ((<|>)) import Control.Arrow (first) import Control.Monad (guard, mplus, msum, mzero, unless, void) import Control.Monad.Except (throwError) import Control.Monad.Reader (ReaderT, ask, asks, lift, local, runReaderT) import Data.Char (isAlphaNum, isLetter) import Data.Default (Default (..), def) import Data.Foldable (for_) import Data.List (isPrefixOf) import Data.List.Split (wordsBy, splitWhen) import qualified Data.Map as M import Data.Maybe (fromMaybe, isJust, isNothing) import Data.Monoid (First (..)) import qualified Data.Set as Set import Data.Text (Text) import qualified Data.Text as T import Network.URI (URI, nonStrictRelativeTo, parseURIReference) import Text.HTML.TagSoup import Text.HTML.TagSoup.Match import Text.Pandoc.Builder (Blocks, HasMeta (..), Inlines, trimInlines) import qualified Text.Pandoc.Builder as B import Text.Pandoc.Class (PandocMonad (..)) import Text.Pandoc.CSS (foldOrElse, pickStyleAttrProps) import Text.Pandoc.Definition import Text.Pandoc.Readers.LaTeX (rawLaTeXInline) import Text.Pandoc.Readers.LaTeX.Types (Macro) import Text.Pandoc.Error import Text.Pandoc.Logging import Text.Pandoc.Options ( Extension (Ext_epub_html_exts, Ext_empty_paragraphs, Ext_native_divs, Ext_native_spans, Ext_raw_html, Ext_line_blocks, Ext_raw_tex), ReaderOptions (readerExtensions, readerStripComments), extensionEnabled) import Text.Pandoc.Parsing hiding ((<|>)) import Text.Pandoc.Shared (addMetaField, blocksToInlines', crFilter, escapeURI, extractSpaces, safeRead, underlineSpan) import Text.Pandoc.Walk import Text.Parsec.Error import Text.TeXMath (readMathML, writeTeX) -- | Convert HTML-formatted string to 'Pandoc' document. readHtml :: PandocMonad m => ReaderOptions -- ^ Reader options -> Text -- ^ String to parse (assumes @'\n'@ line endings) -> m Pandoc readHtml opts inp = do let tags = stripPrefixes . canonicalizeTags $ parseTagsOptions parseOptions{ optTagPosition = True } (crFilter inp) parseDoc = do blocks <- fixPlains False . mconcat <$> manyTill block eof meta <- stateMeta . parserState <$> getState bs' <- replaceNotes (B.toList blocks) reportLogMessages return $ Pandoc meta bs' getError (errorMessages -> ms) = case ms of [] -> "" (m:_) -> messageString m result <- flip runReaderT def $ runParserT parseDoc (HTMLState def{ stateOptions = opts } [] Nothing Set.empty [] M.empty) "source" tags case result of Right doc -> return doc Left err -> throwError $ PandocParseError $ getError err replaceNotes :: PandocMonad m => [Block] -> TagParser m [Block] replaceNotes = walkM replaceNotes' replaceNotes' :: PandocMonad m => Inline -> TagParser m Inline replaceNotes' (RawInline (Format "noteref") ref) = maybe (Str "") (Note . B.toList) . lookup ref <$> getNotes where getNotes = noteTable <$> getState replaceNotes' x = return x data HTMLState = HTMLState { parserState :: ParserState, noteTable :: [(String, Blocks)], baseHref :: Maybe URI, identifiers :: Set.Set String, logMessages :: [LogMessage], macros :: M.Map Text Macro } data HTMLLocal = HTMLLocal { quoteContext :: QuoteContext , inChapter :: Bool -- ^ Set if in chapter section , inPlain :: Bool -- ^ Set if in pPlain } setInChapter :: PandocMonad m => HTMLParser m s a -> HTMLParser m s a setInChapter = local (\s -> s {inChapter = True}) setInPlain :: PandocMonad m => HTMLParser m s a -> HTMLParser m s a setInPlain = local (\s -> s {inPlain = True}) type HTMLParser m s = ParserT s HTMLState (ReaderT HTMLLocal m) type TagParser m = HTMLParser m [Tag Text] pHtml :: PandocMonad m => TagParser m Blocks pHtml = try $ do (TagOpen "html" attr) <- lookAhead pAnyTag for_ (lookup "lang" attr) $ updateState . B.setMeta "lang" . B.text . T.unpack pInTags "html" block pBody :: PandocMonad m => TagParser m Blocks pBody = pInTags "body" block pHead :: PandocMonad m => TagParser m Blocks pHead = pInTags "head" $ pTitle <|> pMetaTag <|> pBaseTag <|> (mempty <$ pAnyTag) where pTitle = pInTags "title" inline >>= setTitle . trimInlines setTitle t = mempty <$ updateState (B.setMeta "title" t) pMetaTag = do mt <- pSatisfy (matchTagOpen "meta" []) let name = T.unpack $ fromAttrib "name" mt if null name then return mempty else do let content = T.unpack $ fromAttrib "content" mt updateState $ \s -> let ps = parserState s in s{ parserState = ps{ stateMeta = addMetaField name (B.text content) (stateMeta ps) } } return mempty pBaseTag = do bt <- pSatisfy (matchTagOpen "base" []) updateState $ \st -> st{ baseHref = parseURIReference $ T.unpack $ fromAttrib "href" bt } return mempty block :: PandocMonad m => TagParser m Blocks block = do res <- choice [ eSection , eSwitch B.para block , mempty <$ eFootnote , mempty <$ eTOC , mempty <$ eTitlePage , pPara , pHeader , pBlockQuote , pCodeBlock , pList , pHrule , pTable , pHtml , pHead , pBody , pLineBlock , pDiv , pPlain , pFigure , pRawHtmlBlock ] trace (take 60 $ show $ B.toList res) return res namespaces :: PandocMonad m => [(String, TagParser m Inlines)] namespaces = [(mathMLNamespace, pMath True)] mathMLNamespace :: String mathMLNamespace = "http://www.w3.org/1998/Math/MathML" eSwitch :: (PandocMonad m, Monoid a) => (Inlines -> a) -> TagParser m a -> TagParser m a eSwitch constructor parser = try $ do guardEnabled Ext_epub_html_exts pSatisfy (matchTagOpen "switch" []) cases <- getFirst . mconcat <$> manyTill (First <$> (eCase <* skipMany pBlank) ) (lookAhead $ try $ pSatisfy (matchTagOpen "default" [])) skipMany pBlank fallback <- pInTags "default" (skipMany pBlank *> parser <* skipMany pBlank) skipMany pBlank pSatisfy (matchTagClose "switch") return $ maybe fallback constructor cases eCase :: PandocMonad m => TagParser m (Maybe Inlines) eCase = do skipMany pBlank TagOpen _ attr' <- lookAhead $ pSatisfy (matchTagOpen "case" []) let attr = toStringAttr attr' case flip lookup namespaces =<< lookup "required-namespace" attr of Just p -> Just <$> pInTags "case" (skipMany pBlank *> p <* skipMany pBlank) Nothing -> Nothing <$ manyTill pAnyTag (pSatisfy (matchTagClose "case")) eFootnote :: PandocMonad m => TagParser m () eFootnote = try $ do let notes = ["footnote", "rearnote"] guardEnabled Ext_epub_html_exts (TagOpen tag attr') <- lookAhead pAnyTag let attr = toStringAttr attr' guard $ maybe False (`elem` notes) (lookup "type" attr) let ident = fromMaybe "" (lookup "id" attr) content <- pInTags tag block addNote ident content addNote :: PandocMonad m => String -> Blocks -> TagParser m () addNote uid cont = updateState (\s -> s {noteTable = (uid, cont) : noteTable s}) eNoteref :: PandocMonad m => TagParser m Inlines eNoteref = try $ do guardEnabled Ext_epub_html_exts TagOpen tag attr' <- lookAhead pAnyTag let attr = toStringAttr attr' guard $ lookup "type" attr == Just "noteref" let ident = maybe "" (dropWhile (== '#')) (lookup "href" attr) guard (not (null ident)) pInTags tag block return $ B.rawInline "noteref" ident -- Strip TOC if there is one, better to generate again eTOC :: PandocMonad m => TagParser m () eTOC = try $ do guardEnabled Ext_epub_html_exts (TagOpen tag attr) <- lookAhead pAnyTag guard $ lookup "type" attr == Just "toc" void (pInTags tag block) pList :: PandocMonad m => TagParser m Blocks pList = pBulletList <|> pOrderedList <|> pDefinitionList pBulletList :: PandocMonad m => TagParser m Blocks pBulletList = try $ do pSatisfy (matchTagOpen "ul" []) let nonItem = pSatisfy (\t -> not (tagOpen (`elem` ["li","ol","ul","dl"]) (const True) t) && not (matchTagClose "ul" t)) -- note: if they have an
    or