In article <Su_L7.44988$RG1.23138548 / news1.rdc1.sfba.home.com>, David Simmons <david.simmons / smallscript.com> wrote: > What we would like is some mechanism to ensure that the two different > versions of #size remain independent. Selector namespaces directly solve > this issue. Actually, they don't. The real issue in this case is that a subclass/method intended for the 1.0.0.0 version of BitTracker is being applied to the 2.0 version. To directly address this problem, you would do something about the: Requires module: BitTracker. "version constraints elided" part of the issue. Modern systems are already pretty good when it comes to issues of version managment. Namespaces, as is so often the case, don't really solve the problem here and unnecessarily complicate matters.