Subject: IPP> PRO - How much IPP request validation can an XML parser do?

From: Tom Hastings <[email-masked]>
Date: Tue, 20 Jan 1998 17:01:58 PST

One advantage that XML might offer is that an XML parser might be able
to perform some amount of request validation, instead of having each 
implementation having to hard code in the validation.  If this were possible,
then interoperability would be increased by using XML, since all 
implementations would be using the same DTD.

Questions that would be helpful for the XML proponents to answer:

1. So how many of the steps in the Model section 15.3 and 15.4 could
be naturally performed by an XML parser, given a DTD for IPP?

  E.g., presence of required attribute groups, order of attribute groups,
  presence of required attributes in required attribute groups,
  attribute syntax is correct for each supplied attribute, etc.  

2. Could an actual implementation take the standard IPP DTD and edit out
the optional features (operations, attributes, and attribute values) that 
the implementation has chosen not to support, and thereby getting further
validation of an IPP operation request?

3. Could an actual implementation take the standard IPP DTD and 
edit in the extensions that the implementation has chosen to support,
and thereby get validation for such extensions in an IPP operation request?

Tom