Hi, I'm playing since a few hours with Parsec and trying to write a small html (fragment) parser, but I'm stuck in a point which I really can't understand.
The problem seem to be either in "parseProperCont" or in "closing" (see code below). It looks like closing does not work (but it is a very simple function!) or (also hard to believe) function "try" from Parsec has some problems. Anyway I get this answer: Prelude ParseSHtml> pf parseHtmlFrg "ptest.txt" Left "ptest.txt" (line 5, column 2): unexpected "/" expecting element name when I'm parsing this file: <div id="normtext"> one line with break<br /> another line <br /><br /> Mail: <a href="mailto:[EMAIL PROTECTED]">[EMAIL PROTECTED]</a> </div> with this code (sorry for the longer mail): import Text.ParserCombinators.Parsec hiding (label) import Text.XHtml.Strict -- Helper function: parse a string up to one of the given chars upTo :: [Char] -> Parser [Char] upTo ds = many1 (noneOf ds) parseHtmlFrg :: Parser Html parseHtmlFrg = do many space choice [parseElem, parseText] <?> "html fragment" parseElem :: Parser Html parseElem = do en <- parseElTag many1 space (ats, cnt) <- restElem en return $ compElem en cnt ! ats <?> "html element" -- Compose a html element from tag name and content compElem en cnt = if isNoHtml cnt then itag en else tag en cnt parseElTag :: Parser String parseElTag = do char '<' en <- elemName return en <?> "element tag" elemName :: Parser String elemName = many1 lower <?> "element name" restElem :: String -> Parser ([HtmlAttr], Html) restElem nm = do ats <- parseAttList ht <- (restElNoCont <|> restElCont nm) return (ats, ht) <?> ("> or /> to close the tag " ++ nm) -- Rest element with no content restElNoCont = do char '/' char '>' return noHtml <?> "/>" -- Rest element with content restElCont nm = do char '>' many space els <- parseProperCont nm return $ concatHtml els <?> "element with content" -- Parse closing tag or proper content(s) parseProperCont :: String -> Parser [Html] parseProperCont nm = try (do closing nm return [] ) <|> (do h <- parseHtmlFrg hs <- parseProperCont nm return (h:hs) ) -- <|> return [] <?> "proper element content" closing nm = do char '<' char '/' nm1 <- elemName char '>' if nm1 == nm then return () else fail $ nm ++ ", encountered " ++ nm1 <?> ("closing of " ++ nm) -- Parse a html attribute parseAttr :: Parser HtmlAttr parseAttr = do at <- many1 lower char '=' va <- parseQuote many space return $ strAttr at va <?> "Attribut" parseAttList = many1 parseAttr <|> return [] <?> "attribute list" -- Parse a quoted string parseQuote :: Parser String parseQuote = do char '"' cs <- upTo ['"'] char '"' return cs -- Parse a text element parseText :: Parser Html parseText = do s <- upTo "<" return (stringToHtml s) <?> "some text" -- For tests: pf p file = parseFromFile p file Nicu _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
