Why do I find myself thinking of roles and classes here? IMHO, we should have a role that represents abstractly a moment in time. This role should, in and of itself, not be tied to any particular calendar; its purpose is so that one can write functions that make reference to instances in time without locking oneself into a particular labeling scheme. We should also have a series of classes that compose that role, each class representing a different calendar scheme. For perl 6.0.0, only one such class need be defined: the one representing the Gregorian calendar. Later on, modules can be written to provide additional classes representing other calendar schemes.
Fine in theory; in practice, the big question is: how much can we get the role to do, within the "no calendar preference" constraint? And a corollary to this: can we get it to do enough to be worthwhile? -- Jonathan "Dataweaver" Lang