be more compatible when importing elementtree, and only in one place

fixes #606

1 files changed, 31 insertions, 0 deletions

diff --git a/rdflib/compat.py b/rdflib/compat.py
index 6c714894..668f5f1a 100644
--- a/rdflib/compat.py
+++ b/rdflib/compat.py
@@ -23,3 +23,34 @@ else:
 
     def numeric_greater(a, b):
         return a > b
+
+
+try:
+  from lxml import etree
+except ImportError:
+  try:
+    # Python 2.5
+    import xml.etree.cElementTree as etree
+  except ImportError:
+    try:
+      # Python 2.5
+      import xml.etree.ElementTree as etree
+    except ImportError:
+      try:
+        # normal cElementTree install
+        import cElementTree as etree
+      except ImportError:
+        try:
+          # normal ElementTree install
+          import elementtree.ElementTree as etree
+        except ImportError:
+          raise Exception("Failed to import ElementTree from any known place")
+
+try:
+    etree_register_namespace = etree.register_namespace
+except AttributeError:
+
+    import xml.etree.ElementTree as etreenative
+
+    def etree_register_namespace(prefix, uri):
+        etreenative._namespace_map[uri] = prefix