I'm a bit confused as to why folks are making pronouncements about their support for this PEP before it's even finished, but, oh well.

As for what seems like one major issue:

Yes, this is a kind of "deferred" evaluation, but it is not a general purpose one, and that, I think, is the strength of the proposal, it's small and specific, and, most importantly, the scope in which the expression will be evaluated is clear and simple. In contrast, a general deferred object would, to me, be really confusing about what scope it would get evaluated in -- I can't even imagine how I would do that -- how the heck am I supposed to know what names will be available in some function scope I pass this thing into??? Also, this would only allow a single expression, not an arbitrary amount of code -- if we're going to have some sort of "deferred object" -- folks will very soon want more than that, and want full deferred function evaluation. So that really is a whole other kettle of fish, and should be considered entirely separately.

As for inspect -- yes, it would be great for these late-evaluated defaults to have a good representation there, but I can only see that as opening the door to more featureful deferred object, certainly not closing it.

-CHB