Added code for xml library (Text.XML.Light) to source tree,

since there is currently no debian package.  Removed
dependency on xml library.  Added license to debian/copyright.


git-svn-id: https://pandoc.googlecode.com/svn/trunk@1351 788f1e2b-df1e-0410-8736-df70ead52e1b

1 files changed, 307 insertions, 0 deletions

diff --git a/Text/XML/Light/Input.hs b/Text/XML/Light/Input.hs
new file mode 100644
index 000000000..3cf3a8cd1
--- /dev/null
+++ b/Text/XML/Light/Input.hs
@@ -0,0 +1,307 @@
+--------------------------------------------------------------------
+-- |
+-- Module    : Text.XML.Light.Input
+-- Copyright : (c) Galois, Inc. 2007
+-- License   : BSD3
+--
+-- Maintainer: Iavor S. Diatchki <diatchki@galois.com>
+-- Stability : provisional
+-- Portability: portable
+--
+-- Lightweight XML parsing
+--
+
+module Text.XML.Light.Input (parseXML,parseXMLDoc) where
+
+import Text.XML.Light.Types
+import Text.XML.Light.Proc
+import Text.XML.Light.Output(tagEnd)
+
+import Data.Char(isSpace)
+import Data.List(isPrefixOf)
+import Numeric(readHex)
+
+-- | parseXMLDoc, parse a XMLl document to maybe an element
+parseXMLDoc  :: String -> Maybe Element
+parseXMLDoc xs  = strip (parseXML xs)
+  where strip cs = case onlyElems cs of
+                    e : es
+                      | "?xml" `isPrefixOf` qName (elName e)
+                          -> strip (map Elem es)
+                      | otherwise -> Just e
+                    _ -> Nothing
+
+-- | parseXML to a list of content chunks
+parseXML   :: String -> [Content]
+parseXML xs = parse $ tokens $ preprocess xs
+
+------------------------------------------------------------------------
+
+parse      :: [Token] -> [Content]
+parse []    = []
+parse ts    = let (es,_,ts1) = nodes ([],Nothing) [] ts
+              in es ++ parse ts1
+
+-- Information about namespaces.
+-- The first component is a map that associates prefixes to URIs,
+-- the second is the URI for the default namespace, if one was provided.
+type NSInfo = ([(String,String)],Maybe String)
+
+nodes :: NSInfo -> [QName] -> [Token] -> ([Content], [QName], [Token])
+
+nodes ns ps (TokCRef ref : ts) =
+  let (es,qs,ts1) = nodes ns ps ts
+  in (CRef ref : es, qs, ts1)
+
+nodes ns ps (TokText txt : ts) =
+  let (es,qs,ts1) = nodes ns ps ts
+      (more,es1)  = case es of
+                      Text cd : es1'
+                        | cdVerbatim cd == cdVerbatim txt -> (cdData cd,es1')
+                      _                                   -> ([],es)
+
+  in (Text txt { cdData = cdData txt ++ more } : es1, qs, ts1)
+
+nodes cur_info ps (TokStart p t as empty : ts) = (node : siblings, open, toks)
+  where
+  new_name  = annotName new_info t
+  new_info  = foldr addNS cur_info as
+  node      = Elem Element { elLine    = Just p
+                           , elName    = new_name
+                           , elAttribs = map (annotAttr new_info) as
+                           , elContent = children
+                           }
+
+  (children,(siblings,open,toks))
+    | empty     = ([], nodes cur_info ps ts)
+    | otherwise = let (es1,qs1,ts1) = nodes new_info (new_name:ps) ts
+                  in (es1,
+                      case qs1 of
+                        [] -> nodes cur_info ps ts1
+                        _ : qs3 -> ([],qs3,ts1))
+
+nodes ns ps (TokEnd p t : ts)   = let t1 = annotName ns t
+                                in case break (t1 ==) ps of
+                                  (as,_:_) -> ([],as,ts)
+                                  -- Unknown closing tag. Insert as text.
+                                  (_,[]) ->
+                                    let (es,qs,ts1) = nodes ns ps ts
+                                    in (Text CData {
+                                               cdLine = Just p,
+                                               cdVerbatim = CDataText,
+                                               cdData = tagEnd t ""
+                                              } : es,qs, ts1)
+
+nodes _ ps []                 = ([],ps,[])
+
+
+annotName :: NSInfo -> QName -> QName
+annotName (namespaces,def_ns) n =
+  n { qURI = maybe def_ns (`lookup` namespaces) (qPrefix n) }
+
+annotAttr :: NSInfo -> Attr -> Attr
+annotAttr ns a@(Attr { attrKey = k}) =
+  case (qPrefix k, qName k) of
+    (Nothing,"xmlns") -> a
+    _                 -> a { attrKey = annotName ns k }
+
+addNS :: Attr -> NSInfo -> NSInfo
+addNS (Attr { attrKey = key, attrVal = val }) (ns,def) =
+  case (qPrefix key, qName key) of
+    (Nothing,"xmlns") -> (ns, if null val then Nothing else Just val)
+    (Just "xmlns", k) -> ((k, val) : ns, def)
+    _                 -> (ns,def)
+
+
+-- Lexer -----------------------------------------------------------------------
+
+type LChar              = (Line,Char)
+type LString            = [LChar]
+data Token              = TokStart Line QName [Attr] Bool  -- is empty?
+                        | TokEnd Line QName
+                        | TokCRef String
+                        | TokText CData
+                          deriving Show
+
+tokens             :: String -> [Token]
+tokens = tokens' . linenumber 1
+
+tokens' :: LString -> [Token]
+tokens' ((_,'<') : c@(_,'!') : cs) = special c cs
+
+tokens' ((_,'<') : cs)   = tag (dropSpace cs) -- we are being nice here
+tokens' [] = []
+tokens' cs@((l,_):_) = let (as,bs) = breakn ('<' ==) cs
+                       in map cvt (decode_text as) ++ tokens' bs
+
+  -- XXX: Note, some of the lines might be a bit inacuarate
+  where cvt (TxtBit x)  = TokText CData { cdLine = Just l
+                                        , cdVerbatim = CDataText
+                                        , cdData = x
+                                        }
+        cvt (CRefBit x) = case cref_to_char x of
+                            Just c -> TokText CData { cdLine = Just l
+                                                    , cdVerbatim = CDataText
+                                                    , cdData = [c]
+                                                    }
+                            Nothing -> TokCRef x
+
+
+special :: LChar -> LString -> [Token]
+special _ ((_,'-') : (_,'-') : cs) = skip cs
+  where skip ((_,'-') : (_,'-') : (_,'>') : ds) = tokens' ds
+        skip (_ : ds) = skip ds
+        skip [] = [] -- unterminated comment
+
+special c ((_,'[') : (_,'C') : (_,'D') : (_,'A') : (_,'T') : (_,'A') : (_,'[')
+         : cs) =
+  let (xs,ts) = cdata cs
+  in TokText CData { cdLine = Just (fst c), cdVerbatim = CDataVerbatim, cdData = xs }
+                                                                  : tokens' ts
+  where cdata ((_,']') : (_,']') : (_,'>') : ds) = ([],ds)
+        cdata ((_,d) : ds)  = let (xs,ys) = cdata ds in (d:xs,ys)
+        cdata []        = ([],[])
+
+special c cs = 
+  let (xs,ts) = munch "" 0 cs
+  in TokText CData { cdLine = Just (fst c), cdVerbatim = CDataRaw, cdData = '<':'!':(reverse xs) } : tokens' ts
+  where munch acc nesting ((_,'>') : ds) 
+         | nesting == (0::Int) = ('>':acc,ds)
+	 | otherwise           = munch ('>':acc) (nesting-1) ds
+        munch acc nesting ((_,'<') : ds)
+	 = munch ('<':acc) (nesting+1) ds
+        munch acc n ((_,x) : ds) = munch (x:acc) n ds
+        munch acc _ [] = (acc,[]) -- unterminated DTD markup
+
+--special c cs = tag (c : cs) -- invalid specials are processed as tags
+
+
+qualName           :: LString -> (QName,LString)
+qualName xs         = let (as,bs) = breakn endName xs
+                          (q,n)   = case break (':'==) as of
+                                      (q1,_:n1) -> (Just q1, n1)
+                                      _         -> (Nothing, as)
+                      in (QName { qURI = Nothing, qPrefix = q, qName = n }, bs)
+  where endName x = isSpace x || x == '=' || x == '>' || x == '/'
+
+
+
+
+
+tag              :: LString -> [Token]
+tag ((p,'/') : cs)    = let (n,ds) = qualName (dropSpace cs)
+                        in TokEnd p n : case ds of
+                                          (_,'>') : es -> tokens' es
+                                          -- tag was not properly closed...
+                                          _        -> tokens' ds
+tag []            = []
+tag cs            = let (n,ds)  = qualName cs
+                        (as,b,ts) = attribs (dropSpace ds)
+                    in TokStart (fst (head cs)) n as b : ts
+
+attribs          :: LString -> ([Attr], Bool, [Token])
+attribs cs        = case cs of
+                      (_,'>') : ds -> ([], False, tokens' ds)
+
+                      (_,'/') : ds -> ([], True, case ds of
+                                              (_,'>') : es -> tokens' es
+                                              -- insert missing >  ...
+                                              _ -> tokens' ds)
+
+                      (_,'?') : (_,'>') : ds -> ([], True, tokens' ds)
+
+                      -- doc ended within a tag..
+                      []       -> ([],False,[])
+
+                      _        -> let (a,cs1) = attrib cs
+                                      (as,b,ts) = attribs cs1
+                                  in (a:as,b,ts)
+
+attrib             :: LString -> (Attr,LString)
+attrib cs           = let (ks,cs1)  = qualName cs
+                          (vs,cs2)  = attr_val (dropSpace cs1)
+                      in ((Attr ks (decode_attr vs)),dropSpace cs2)
+
+attr_val           :: LString -> (String,LString)
+attr_val ((_,'=') : cs) = string (dropSpace cs)
+attr_val cs         = ("",cs)
+
+
+dropSpace :: LString -> LString
+dropSpace = dropWhile (isSpace . snd)
+
+-- | Match the value for an attribute.  For malformed XML we do
+-- our best to guess the programmer's intention.
+string             :: LString -> (String,LString)
+string ((_,'"') : cs)   = break' ('"' ==) cs
+
+-- Allow attributes to be enclosed between ' '.
+string ((_,'\'') : cs)  = break' ('\'' ==) cs
+
+-- Allow attributes that are not enclosed by anything.
+string cs           = breakn eos cs
+  where eos x = isSpace x || x == '>' || x == '/'
+
+
+break' :: (a -> Bool) -> [(b,a)] -> ([a],[(b,a)])
+break' p xs         = let (as,bs) = breakn p xs
+                      in (as, case bs of
+                                [] -> []
+                                _ : cs -> cs)
+
+breakn :: (a -> Bool) -> [(b,a)] -> ([a],[(b,a)])
+breakn p l = (map snd as,bs) where (as,bs) = break (p . snd) l
+
+
+
+decode_attr :: String -> String
+decode_attr cs = concatMap cvt (decode_text cs)
+  where cvt (TxtBit x) = x
+        cvt (CRefBit x) = case cref_to_char x of
+                            Just c -> [c]
+                            Nothing -> '&' : x ++ ";"
+
+data Txt = TxtBit String | CRefBit String deriving Show
+
+decode_text :: [Char] -> [Txt]
+decode_text xs@('&' : cs) = case break (';' ==) cs of
+                              (as,_:bs) -> CRefBit as : decode_text bs
+                              _ -> [TxtBit xs]
+decode_text []  = []
+decode_text cs  = let (as,bs) = break ('&' ==) cs
+                  in TxtBit as : decode_text bs
+
+cref_to_char :: [Char] -> Maybe Char
+cref_to_char cs = case cs of
+  '#' : ds  -> num_esc ds
+  "lt"      -> Just '<'
+  "gt"      -> Just '>'
+  "amp"     -> Just '&'
+  "apos"    -> Just '\''
+  "quot"    -> Just '"'
+  _         -> Nothing
+
+num_esc :: String -> Maybe Char
+num_esc cs = case cs of
+               'x' : ds -> check (readHex ds)
+               _        -> check (reads cs)
+
+  where check [(n,"")]  = cvt_char n
+        check _         = Nothing
+
+cvt_char :: Int -> Maybe Char
+cvt_char x
+  | fromEnum (minBound :: Char) <= x && x <= fromEnum (maxBound::Char)
+                = Just (toEnum x)
+  | otherwise = Nothing
+
+preprocess :: String -> String
+preprocess ('\r' : '\n' : cs) = '\n' : preprocess cs
+preprocess ('\r' : cs)        = '\n' : preprocess cs
+preprocess (c : cs)           = c : preprocess cs
+preprocess []                 = []
+
+linenumber :: Line -> String -> LString
+linenumber _ [] = []
+linenumber n ('\n':s) = n' `seq` ((n,'\n'):linenumber n' s) where n' = n + 1
+linenumber n (c:s)    = (n,c) : linenumber n s