pandoc/Text/Pandoc/XML.hs

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{-
Copyright (C) 2006-7 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) 2006-7 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 ( escapeCharForXML,
escapeStringForXML,
inTags,
selfClosingTag,
inTagsSimple,
inTagsIndented ) where
import Text.PrettyPrint.HughesPJ
-- | Escape one character as needed for XML.
escapeCharForXML :: Char -> String
escapeCharForXML x = case x of
'&' -> "&amp;"
'<' -> "&lt;"
'>' -> "&gt;"
'"' -> "&quot;"
'\160' -> "&#160;"
c -> [c]
-- | True if the character needs to be escaped.
needsEscaping :: Char -> Bool
needsEscaping c = c `elem` "&<>\"\160"
-- | Escape string as needed for XML. Entity references are not preserved.
escapeStringForXML :: String -> String
escapeStringForXML "" = ""
escapeStringForXML str =
case break needsEscaping str of
(okay, "") -> okay
(okay, (c:cs)) -> okay ++ escapeCharForXML c ++ escapeStringForXML cs
-- | Return a text object with a string of formatted XML attributes.
attributeList :: [(String, String)] -> Doc
attributeList = text . concatMap
(\(a, b) -> " " ++ escapeStringForXML a ++ "=\"" ++
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 []