Package DOM attributes for Node objects

The Supplement type did the needed mapping (using nodeValue when the
value wasn't a string) and it turns out to be useful to do the same
for the DOM object packaged by a Node, too. Pull out into a helper
function, use dict-comprehension and expose as a method of Node.

Change-Id: Ice6737a54a33372b45cf42152e3fdbf5f2da7ba4
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

util/locale_database/ldml.py

@@ -21,6 +21,10 @@ See individual classes for further detail.
 from localetools import Error
 from dateconverter import convert_date
 
+def _attrsFromDom(dom):
+    return { k: (v if isinstance(v, str) else v.nodeValue)
+             for k, v in dom.attributes.items() }
+
 class Node (object):
     """Wrapper for an arbitrary DOM node.
 
@@ -50,6 +54,9 @@ class Node (object):
         else:
             self.draft = max(draft, self.draftScore(attr))
 
+    def attributes(self):
+        return _attrsFromDom(self.dom)
+
     def findAllChildren(self, tag, wanted = None, allDull = False):
         """All children that do have the given tag and attributes.
 
@@ -184,9 +191,7 @@ class Supplement (XmlScanner):
                                 if not any(a in e.dom.attributes
                                            for a in exclude)):
             if elt.attributes:
-                yield (elt.nodeName,
-                       dict((k, v if isinstance(v, str) else v.nodeValue)
-                            for k, v in elt.attributes.items()))
+                yield elt.nodeName, _attrsFromDom(elt)
 
 class LocaleScanner (object):
     def __init__(self, name, nodes, root):