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{-
Copyright (C) 2006-2010 John MacFarlane <jgm@berkeley.edu>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-}
{- |
Module : Text.Pandoc.XML
Copyright : Copyright (C) 2006-2010 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Functions for escaping and formatting XML.
-}
module Text.Pandoc.XML ( stripTags,
escapeCharForXML,
escapeStringForXML,
inTags,
selfClosingTag,
inTagsSimple,
inTagsIndented,
toEntities,
fromEntities ) where
import Text.Pandoc.Pretty
import Data.Char (ord, isAscii, isSpace)
import Text.HTML.TagSoup.Entity (lookupEntity)
-- | Remove everything between <...>
stripTags :: String -> String
stripTags ('<':xs) =
let (_,rest) = break (=='>') xs
in if null rest
then ""
else stripTags (tail rest) -- leave off >
stripTags (x:xs) = x : stripTags xs
stripTags [] = []
-- | Escape one character as needed for XML.
escapeCharForXML :: Char -> String
escapeCharForXML x = case x of
'&' -> "&"
'<' -> "<"
'>' -> ">"
'"' -> """
c -> [c]
-- | Escape string as needed for XML. Entity references are not preserved.
escapeStringForXML :: String -> String
escapeStringForXML = concatMap escapeCharForXML
-- | Escape newline characters as
escapeNls :: String -> String
escapeNls (x:xs)
| x == '\n' = " " ++ escapeNls xs
| otherwise = x : escapeNls xs
escapeNls [] = []
-- | Return a text object with a string of formatted XML attributes.
attributeList :: [(String, String)] -> Doc
attributeList = hcat . map
(\(a, b) -> text (' ' : escapeStringForXML a ++ "=\"" ++
escapeNls (escapeStringForXML b) ++ "\""))
-- | Put the supplied contents between start and end tags of tagType,
-- with specified attributes and (if specified) indentation.
inTags:: Bool -> String -> [(String, String)] -> Doc -> Doc
inTags isIndented tagType attribs contents =
let openTag = char '<' <> text tagType <> attributeList attribs <>
char '>'
closeTag = text "</" <> text tagType <> char '>'
in if isIndented
then openTag $$ nest 2 contents $$ closeTag
else openTag <> contents <> closeTag
-- | Return a self-closing tag of tagType with specified attributes
selfClosingTag :: String -> [(String, String)] -> Doc
selfClosingTag tagType attribs =
char '<' <> text tagType <> attributeList attribs <> text " />"
-- | Put the supplied contents between start and end tags of tagType.
inTagsSimple :: String -> Doc -> Doc
inTagsSimple tagType = inTags False tagType []
-- | Put the supplied contents in indented block btw start and end tags.
inTagsIndented :: String -> Doc -> Doc
inTagsIndented tagType = inTags True tagType []
-- | Escape all non-ascii characters using numerical entities.
toEntities :: String -> String
toEntities [] = ""
toEntities (c:cs)
| isAscii c = c : toEntities cs
| otherwise = "&#" ++ show (ord c) ++ ";" ++ toEntities cs
-- Unescapes XML entities
fromEntities :: String -> String
fromEntities ('&':xs) =
case lookupEntity ent of
Just c -> c : fromEntities rest
Nothing -> '&' : fromEntities xs
where (ent, rest) = case break (\c -> isSpace c || c == ';') xs of
(zs,';':ys) -> (zs,ys)
_ -> ("",xs)
fromEntities (x:xs) = x : fromEntities xs
fromEntities [] = []
|
