Implement iterkeys on top of __iter__ instead of vice versa. Thanks to Brian Harring for the suggestion. (trunk r6918)

svn path=/main/branches/2.1.2/; revision=6934

1 files changed, 11 insertions, 1 deletions

diff --git a/pym/cache/template.py b/pym/cache/template.py
index d19bb8892..6457f59e5 100644
--- a/pym/cache/template.py
+++ b/pym/cache/template.py
@@ -95,7 +95,7 @@ class database(object):
 		return tuple(self.iterkeys())
 
 	def iterkeys(self):
-		raise NotImplementedError
+		return iter(self)
 
 	def iteritems(self):
 		for x in self.iterkeys():
@@ -123,6 +123,16 @@ class database(object):
 			raise NotImplementedError
 		return self.has_key(cpv)
 
+	def __iter__(self):
+		"""This method should always be overridden.  It is provided only for
+		backward compatibility with modules that override iterkeys instead.  It
+		will automatically raise a NotImplementedError if iterkeys has not been
+		overridden."""
+		if self.iterkeys is database.iterkeys:
+			# prevent a possible recursive loop
+			raise NotImplementedError(self)
+		return self.iterkeys()
+
 	def get(self, k, x=None):
 		try:
 			return self[k]