RE: Can SOAP be called a XML protocol ? [was: why no doc type declaration and PIs in SOAP?]

I am not sure I agree.  I think SOAP is an application of XML, not a 
dialect.  Any application of XML can say in its specification:  "my 
vocabulary doesn't use attributes",  "the integer value of attribute WIDTH 
must be greater than or equal to HEIGHT", "the root element must be 
ENVELOPE"  or "no PI's allowed".  Some of these constraints are 
enforceable by schemas, some by XML 1.0 itself, some only by 
application-specific mechanisms. 

So it is with SOAP.  It's an application of XML.  Its specification 
defines the subset of XML used for that application.  That's true of 
almost every application of XML, and I think it's appropriate.  If this is 
a slippery slope, then I think most applications of XML are on a similar 

I think what people are looking for is not so much to avoid subsetting 
XML, but to reuse off-the-shelf parsers.   Well, if those parsers 
correctly report the existence of DTDs and PIs to your applications, you 
can.  Your SOAP code should report an error when those constructs are 
signalled by the parser.  If you want to build an optimized processor that 
knows how much faster it can run because it never has to worry about 
DTD's, good for you.  There are lots of XML processors out there that 
really only read one vocabulary, and you've just built another one.

So, I think it's all OK, and should remain as it is.

Noah Mendelsohn                                    Voice: 1-617-693-4036
Lotus Development Corp.                            Fax: 1-617-693-8676
One Rogers Street
Cambridge, MA 02142

"Andrew Layman" <>
Sent by:
09/21/01 02:38 PM

        To:     <>
        cc:     (bcc: Noah Mendelsohn/CAM/Lotus)
        Subject:        RE: Can SOAP be called a XML protocol ? [was: why no doc type declaration 
and PIs in SOAP?]

I agree with Eric van der Vlist's mail.  Subsetting XML for SOAP starts
on a slippery slope to having multiple, incompatible dialects of XML. If
a profile of XML is thought needed for certain classes of device, then
this should be explicitly addressed as an XML issue, not a SOAP issue.

Received on Friday, 21 September 2001 15:52:25 UTC