Docx reader: use Map instead of list for Namespaces.

This gives a speedup of about 5-10%.

The reader is now approximately twice as fast as in the last
release.

2 files changed, 20 insertions, 20 deletions

diff --git a/src/Text/Pandoc/Readers/Docx/Parse.hs b/src/Text/Pandoc/Readers/Docx/Parse.hs
index c76f3c171..f8ed248d7 100644
--- a/src/Text/Pandoc/Readers/Docx/Parse.hs
+++ b/src/Text/Pandoc/Readers/Docx/Parse.hs
@@ -396,9 +396,9 @@ archiveToNotes zf =
                >>= parseXMLFromEntry
       enElem = findEntryByPath "word/endnotes.xml" zf
                >>= parseXMLFromEntry
-      fn_namespaces = maybe [] elemToNameSpaces fnElem
-      en_namespaces = maybe [] elemToNameSpaces enElem
-      ns = unionBy (\x y -> fst x == fst y) fn_namespaces en_namespaces
+      fn_namespaces = maybe mempty elemToNameSpaces fnElem
+      en_namespaces = maybe mempty elemToNameSpaces enElem
+      ns = M.union fn_namespaces en_namespaces
       fn = fnElem >>= elemToNotes ns "footnote" . walkDocument ns
       en = enElem >>= elemToNotes ns "endnote" . walkDocument ns
   in
@@ -408,7 +408,7 @@ archiveToComments :: Archive -> Comments
 archiveToComments zf =
   let cmtsElem = findEntryByPath "word/comments.xml" zf
                >>= parseXMLFromEntry
-      cmts_namespaces = maybe [] elemToNameSpaces cmtsElem
+      cmts_namespaces = maybe mempty elemToNameSpaces cmtsElem
       cmts = elemToComments cmts_namespaces . walkDocument cmts_namespaces <$>
                cmtsElem
   in
@@ -518,7 +518,7 @@ levelElemToLevel _ _ = Nothing
 archiveToNumbering' :: Archive -> Maybe Numbering
 archiveToNumbering' zf =
   case findEntryByPath "word/numbering.xml" zf of
-    Nothing -> Just $ Numbering [] [] []
+    Nothing -> Just $ Numbering mempty [] []
     Just entry -> do
       numberingElem <- parseXMLFromEntry entry
       let namespaces = elemToNameSpaces numberingElem
@@ -530,7 +530,7 @@ archiveToNumbering' zf =
 
 archiveToNumbering :: Archive -> Numbering
 archiveToNumbering archive =
-  fromMaybe (Numbering [] [] []) (archiveToNumbering' archive)
+  fromMaybe (Numbering mempty [] []) (archiveToNumbering' archive)
 
 elemToNotes :: NameSpaces -> Text -> Element -> Maybe (M.Map T.Text Element)
 elemToNotes ns notetype element
@@ -875,7 +875,7 @@ childElemToRun ns element
   = let (title, alt) = getTitleAndAlt ns element
         a_ns = "http://schemas.openxmlformats.org/drawingml/2006/main"
         drawing = findElement (QName "blip" (Just a_ns) (Just "a")) picElem
-                  >>= findAttr (QName "embed" (lookup "r" ns) (Just "r"))
+                  >>= findAttr (QName "embed" (M.lookup "r" ns) (Just "r"))
     in
      case drawing of
        Just s -> expandDrawingId s >>=
diff --git a/src/Text/Pandoc/Readers/Docx/Util.hs b/src/Text/Pandoc/Readers/Docx/Util.hs
index 21df03d9e..ac331cba6 100644
--- a/src/Text/Pandoc/Readers/Docx/Util.hs
+++ b/src/Text/Pandoc/Readers/Docx/Util.hs
@@ -22,42 +22,42 @@ module Text.Pandoc.Readers.Docx.Util (
                                       , findAttrByName
                                       ) where
 
-import Data.Maybe (mapMaybe)
 import qualified Data.Text as T
 import Data.Text (Text)
 import Text.Pandoc.XML.Light
+import qualified Data.Map as M
 
-type NameSpaces = [(Text, Text)]
+type NameSpaces = M.Map Text Text
 
 elemToNameSpaces :: Element -> NameSpaces
-elemToNameSpaces = mapMaybe attrToNSPair . elAttribs
-
-attrToNSPair :: Attr -> Maybe (Text, Text)
-attrToNSPair (Attr (QName s _ (Just "xmlns")) val) = Just (s, val)
-attrToNSPair _                                     = Nothing
+elemToNameSpaces = foldr (\(Attr qn val) ->
+                             case qn of
+                               QName s _ (Just "xmlns") -> M.insert s val
+                               _ -> id) mempty . elAttribs
 
 elemName :: NameSpaces -> Text -> Text -> QName
 elemName ns prefix name =
-  QName name (lookup prefix ns) (if T.null prefix then Nothing else Just prefix)
+  QName name (M.lookup prefix ns)
+             (if T.null prefix then Nothing else Just prefix)
 
 isElem :: NameSpaces -> Text -> Text -> Element -> Bool
 isElem ns prefix name element =
-  let ns' = ns ++ elemToNameSpaces element
+  let ns' = ns <> elemToNameSpaces element
   in qName (elName element) == name &&
-     qURI (elName element) == lookup prefix ns'
+     qURI (elName element) == M.lookup prefix ns'
 
 findChildByName :: NameSpaces -> Text -> Text -> Element -> Maybe Element
 findChildByName ns pref name el =
-  let ns' = ns ++ elemToNameSpaces el
+  let ns' = ns <> elemToNameSpaces el
   in  findChild (elemName ns' pref name) el
 
 findChildrenByName :: NameSpaces -> Text -> Text -> Element -> [Element]
 findChildrenByName ns pref name el =
-  let ns' = ns ++ elemToNameSpaces el
+  let ns' = ns <> elemToNameSpaces el
   in  findChildren (elemName ns' pref name) el
 
 findAttrByName :: NameSpaces -> Text -> Text -> Element -> Maybe Text
 findAttrByName ns pref name el =
-  let ns' = ns ++ elemToNameSpaces el
+  let ns' = ns <> elemToNameSpaces el
   in  findAttr (elemName ns' pref name) el