id	summary	reporter	owner	description	type	status	priority	component	severity	resolution	keywords	cc
53	Allow for immutable subclasses of YAMLObject	toidinamai	xi	"YAMLObject are not directly instantiated so they don't need their own
instance attribute (i.e. an own dict). Because of that they should define
an empty __slots__ and let subclasses decide whether they want arbitrary
instance attributes or not:

{{{
--- lib/yaml/__init__.py        (revision 251)
+++ lib/yaml/__init__.py        (working copy)
@@ -272,6 +272,9 @@
     yaml_tag = None
     yaml_flow_style = None
 
+    # no direct instantiation, so allow for immutable subclasses
+    __slots__ = ()
+
     def from_yaml(cls, loader, node):
         """"""
         Convert a representation node to a Python object.
}}}

The same is basically also true for YAMLObjectMetaclass but I doubt there
is much use for this in practice."	enhancement	closed	normal	pyyaml	trivial	fixed