Moved general XML stuff to GF.Data.XML. Started working on VoiceXML generation.

src/GF/Data/XML.hs

@@ -0,0 +1,46 @@
+----------------------------------------------------------------------
+-- |
+-- Module      : XML
+-- Maintainer  : BB
+-- Stability   : (stable)
+-- Portability : (portable)
+--
+-- Utilities for creating XML documents.
+-----------------------------------------------------------------------------
+
+module GF.Data.XML (XML(..), Attr, comments, showsXMLDoc, showsXML) where
+
+import GF.Data.Utilities
+
+data XML = Data String | Tag String [Attr] [XML] | Comment String
+ deriving (Eq,Show)
+
+type Attr = (String,String)
+
+comments :: [String] -> [XML]
+comments = map Comment
+
+showsXMLDoc :: XML -> ShowS
+showsXMLDoc xml = showString header . showsXML xml 
+  where header = "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>"
+
+showsXML :: XML -> ShowS
+showsXML (Data s) = showString s
+showsXML (Tag t as []) = showChar '<' . showString t . showsAttrs as . showString "/>"
+showsXML (Tag t as cs) = 
+    showChar '<' . showString t . showsAttrs as . showChar '>' 
+		 . concatS (map showsXML cs) . showString "</" . showString t . showChar '>'
+showsXML (Comment c) = showString "<!-- " . showString c . showString " -->"
+
+showsAttrs :: [Attr] -> ShowS
+showsAttrs = concatS . map (showChar ' ' .) . map showsAttr
+
+showsAttr :: Attr -> ShowS
+showsAttr (n,v) = showString n . showString "=\"" . showString (escape v) . showString "\""
+
+-- FIXME: escape strange charachters with &#xxx;
+escape :: String -> String
+escape = concatMap escChar
+  where
+  escChar c | c `elem` ['"','\\'] = '\\':[c]
+            | otherwise = [c]