Partially resolving templates on the back end

[dmlayton]

I am writing a HAL interface and I have a template like blah{/foo,bar}/blah{/baz}. Since foo and bar are attributes of a parent resource, I need to give back a uri template like blah/foo_value/bar_value/blah{/baz}
However, expand quite righly returns
blah/foo_value/bar_value/blah
because that is what a client should do, but I am the server. Is there anyway to have an option to partially resolve the template?