It's a start, at least.

5 files changed, 31 insertions, 16 deletions

diff --git a/bs4/__init__.py b/bs4/__init__.py
index 98ac57b..786b57b 100644
--- a/bs4/__init__.py
+++ b/bs4/__init__.py
@@ -193,9 +193,9 @@ class BeautifulSoup(Tag):
         self.tagStack = []
         self.pushTag(self)
 
-    def new_tag(self, name, **attrs):
+    def new_tag(self, name, namespace=None, **attrs):
         """Create a new tag associated with this soup."""
-        return Tag(None, self.builder, name, attrs)
+        return Tag(None, self.builder, name, namespace, attrs)
 
     def new_string(self, s):
         """Create a new NavigableString associated with this soup."""
@@ -272,7 +272,7 @@ class BeautifulSoup(Tag):
             mostRecentTag = self.popTag()
         return mostRecentTag
 
-    def handle_starttag(self, name, attrs):
+    def handle_starttag(self, name, namespace, attrs):
         """Push a start tag on to the stack.
 
         If this method returns None, the tag was rejected by the
@@ -289,7 +289,7 @@ class BeautifulSoup(Tag):
                  or not self.parse_only.search_tag(name, attrs))):
             return None
 
-        tag = Tag(self, self.builder, name, attrs, self.currentTag,
+        tag = Tag(self, self.builder, name, namespace, attrs, self.currentTag,
                   self.previous_element)
         if tag is None:
             return tag
diff --git a/bs4/builder/_html5lib.py b/bs4/builder/_html5lib.py
index 0d7a1a9..7ce69aa 100644
--- a/bs4/builder/_html5lib.py
+++ b/bs4/builder/_html5lib.py
@@ -8,6 +8,7 @@ from bs4.builder import (
     HTML_5,
     HTMLTreeBuilder,
     )
+from bs4.element import NamespacedAttribute
 import html5lib
 from html5lib.constants import (
     DataLossWarning,
@@ -58,9 +59,6 @@ class TreeBuilderForHtml5lib(html5lib.treebuilders._base.TreeBuilder):
 
     def __init__(self, soup, namespaceHTMLElements):
         self.soup = soup
-        if namespaceHTMLElements:
-            warnings.warn("namespaceHTMLElements not supported yet",
-                          DataLossWarning)
         super(TreeBuilderForHtml5lib, self).__init__(namespaceHTMLElements)
 
     def documentClass(self):
@@ -76,9 +74,7 @@ class TreeBuilderForHtml5lib(html5lib.treebuilders._base.TreeBuilder):
         self.soup.object_was_parsed(doctype)
 
     def elementClass(self, name, namespace):
-        if namespace is not None:
-            warnings.warn("BeautifulSoup cannot represent elements in any namespace", DataLossWarning)
-        tag = self.soup.new_tag(name)
+        tag = self.soup.new_tag(name, namespace)
         return Element(tag, self.soup, namespace)
 
     def commentClass(self, data):
@@ -144,6 +140,8 @@ class Element(html5lib.treebuilders._base.Node):
     def setAttributes(self, attributes):
         if attributes is not None and attributes != {}:
             for name, value in list(attributes.items()):
+                if isinstance(name, tuple):
+                    name = NamespacedAttribute(*name)
                 self.element[name] =  value
             # The attributes may contain variables that need substitution.
             # Call set_up_substitutions manually.
@@ -189,7 +187,7 @@ class Element(html5lib.treebuilders._base.Node):
                     TextNode(child, self.soup))
 
     def cloneNode(self):
-        tag = self.soup.new_tag(self.element.name)
+        tag = self.soup.new_tag(self.element.name, self.namespace)
         node = Element(tag, self.soup, self.namespace)
         for key,value in self.attributes:
             node.attributes[key] = value
diff --git a/bs4/builder/_htmlparser.py b/bs4/builder/_htmlparser.py
index c785eed..ec6d456 100644
--- a/bs4/builder/_htmlparser.py
+++ b/bs4/builder/_htmlparser.py
@@ -68,7 +68,8 @@ class HTMLParserTreeBuilder(HTMLParser, HTMLTreeBuilder):
         super(HTMLParserTreeBuilder, self).feed(markup)
 
     def handle_starttag(self, name, attrs):
-        self.soup.handle_starttag(name, dict(attrs))
+        # XXX namespace
+        self.soup.handle_starttag(name, None, dict(attrs))
 
     def handle_endtag(self, name):
         self.soup.handle_endtag(name)
diff --git a/bs4/builder/_lxml.py b/bs4/builder/_lxml.py
index cc3cb86..985a030 100644
--- a/bs4/builder/_lxml.py
+++ b/bs4/builder/_lxml.py
@@ -66,7 +66,8 @@ class LXMLTreeBuilderForXML(TreeBuilder):
         pass
 
     def start(self, name, attrs):
-        self.soup.handle_starttag(name, attrs)
+        # XXX namespace
+        self.soup.handle_starttag(name, None, attrs)
 
     def end(self, name):
         self.soup.endData()
diff --git a/bs4/element.py b/bs4/element.py
index 513407c..926fb8f 100644
--- a/bs4/element.py
+++ b/bs4/element.py
@@ -22,6 +22,20 @@ def _alias(attr):
     return alias
 
 
+class NamespacedAttribute(object):
+
+    def __init__(self, namespace_abbreviation, name, namespace):
+        self.namespace_abbreviation = namespace_abbreviation
+        self.name = name
+        self.namespace = namespace
+
+    def __str__(self):
+        name = self.name
+        if self.namespace_abbreviation:
+            name = self.namespace_abbreviation + ":" + name
+        return name
+
+
 class PageElement(object):
     """Contains the navigational information for some part of the page
     (either a tag or a piece of text)"""
@@ -507,8 +521,8 @@ class Tag(PageElement):
 
     """Represents a found HTML tag with its attributes and contents."""
 
-    def __init__(self, parser=None, builder=None, name=None, attrs=None,
-                 parent=None, previous=None):
+    def __init__(self, parser=None, builder=None, name=None, namespace=None,
+                 attrs=None, parent=None, previous=None):
         "Basic constructor."
 
         if parser is None:
@@ -520,6 +534,7 @@ class Tag(PageElement):
         if name is None:
             raise ValueError("No value provided for new tag's name.")
         self.name = name
+        self.namespace = namespace
         if attrs is None:
             attrs = {}
         else:
@@ -779,7 +794,7 @@ class Tag(PageElement):
                         and '%SOUP-ENCODING%' in val):
                         val = self.substitute_encoding(val, eventual_encoding)
 
-                    decoded = (key + '='
+                    decoded = (str(key) + '='
                                + EntitySubstitution.substitute_xml(val, True))
                 attrs.append(decoded)
         close = ''