As I talked about in the previous commit, this is going to be the
replacement for the aggreagte `attr_parse!`; the next commit will integrate
it into `ele_parse!` so that I can begin to remove the old one.
It is disappointing, since I did put a bit of work into this and I think the
end result was pretty neat, even if was never fully utilized. But, this
simplifies things significantly; no use in maintaining features that serve
no purpose but to confound people.
DEV-13346
Mike Gerwitz