On Monday, 4 June 2012 at 20:26:52 UTC, Steven Schveighoffer wrote: > On Mon, 04 Jun 2012 16:13:49 -0400, Mehrdad >> Can you use "null"? > > Hm... now that null has its own type, I likely could. > > I suppose that would map properly to 0. > > -Steve But if the key is non-nullable this might be confusing, or even not possible.