I agree that a (first-class) Interpreter object is already present
(but not properly exposed) in IPP/1.0 with the 'coloring' of
'xxx-supported' by 'document-format' operation attribute in
GetPrinterAttributes.
I also believe we need to have a first-class Document object in
IPP.
OO arguments aside (and they *are* good arguments), the implicit
Interpreter object is (as Carl has observed) the *actual* target
of CreateJob. If you specify 'document-format', it's that
Interpreter. If you don't, you get the one selected by
'document-format-default'.
And real schedulers often fill the pipelines of all of their
interpreters from the pool of jobs currently spooled (or
spooling if they 'sniff' the PDL of incoming jobs).
The present object-poor IPP model is becoming a progressively
more obvious constraint during the discussions on the additional
system admin operations.
Cheers,
- Ira McDonald
High North Inc