[mdx] GH issue 3: lookup based on entity attributes

[Tom Scavo]

On Wed, Nov 27, 2013 at 10:45 AM, Ian Young <ian at iay.org.uk> wrote:
>
> The usual question needs to be: is there a near-term, concrete use case for this ability, or does having the responder assign an identifier to an arbitrary collection suffice for the moment?

I don't understand. If only (3) is supported, how will a responder
know when the ID is an entityID or the value of an entity attribute?
Seems like case (2) (at least) is needed.

Tom