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- Date: Tue, 08 Aug 2006 22:21:10 +0000
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http://www.w3.org/Bugs/Public/show_bug.cgi?id=3589 Summary: Definitions of "schema document" draft proposal for bugs 2822 and 2846 PSVI and processor profiles Product: XML Schema Version: 1.1 only Platform: PC OS/Version: Windows XP Status: NEW Severity: normal Priority: P2 Component: Structures: XSD Part 1 AssignedTo: cmsmcq@w3.org ReportedBy: noah_mendelsohn@us.ibm.com QAContact: www-xml-schema-comments@w3.org CC: noah_mendelsohn@us.ibm.com Definitions of "schema document" draft proposal for bugs 2822 and 2846 PSVI and processor profiles This is to get into bugzilla a comment I made on the Telcon of 4 Aug 2006. The draft at [1] says: "It is implementation-defined whether a schema processor can read schema documents in the XML transfer syntax defined here, or in the form of information sets which correspond to the XML syntax. (See Conformance (§2.4), which defines "·minimally conforming·" processors as those which cannot read schema documents in XML form, and "·schema-document aware·" processors as those which can.)" My main concern is specifically with the text "schema documents in the XML transfer syntax defined here", which raises the question of what it means for something to be "defined" in our recommendation. My strong preference is that we reserve the term "defined" for things which are marked up as:"[Definition:] XXXX". In the particular case of the term -schema document- we have: "To provide for this in an appropriate and interoperable way, this specification provides a normative XML representation for schemas which makes provision for every kind of schema component. [Definition:] A document in this form (i.e. a <schema> element information item) is a schema document. " I think that's pretty clear that what we define as a schema document is an "element information item", and hence an abstract Infoset. Taking that narrow view of what it means for something to be defined in our recommendation, I don't think we define an XML Transfer Syntax for XML Schema Documents. I think the closest we come is in [3], where we say: "For interoperability, serialized ·schema documents·, like all other Web resources, should be identified by URI and retrieved using the standard mechanisms of the Web (e.g. http, https, etc.) Such documents on the Web must be part of XML documents (see clause 1.1), and are represented in the standard XML schema definition form described by layer 2 (that is as <schema> element information items). Note: there will often be times when a schema document will be a complete XML document whose document element is <schema>. There will be other occasions in which <schema> items will be contained in other documents, perhaps referenced using fragment and/or XPointer notation. " Here I think we're referring to serializations, but not >defining< anything. For the same reason, I'm concerned about the phrase that says: "or in the form of information sets which correspond to the XML syntax". That comes close to implying that we only define the serialization, but by the way there is a corresponding Infoset. For the reasons quoted above, I think the reverse is true. The formal definition of schema document is as an infoset, and by the way there is for each such Infoset a class of schema documents that correspond (differing, e.g. in whether their attributes use single quotes, the order of attribute serialization, etc.) To be clear, I don't object to the spirit of what I think [1] is trying to say, just to the exact way it's stated. In the spirit of offering concrete alternatives when there's a concern, I can think of at least two that would be fine with me, and I'm sure there are many other simple fixes that would be fine too: Alternative 1: "The exact form in which XML Schema documents are conveyed to a schema processor is implementation dependent. In particular, they MAY be read, either from the Web or from other sources, in the form of XML 1.x serializations, and/or they MAY be conveyed through other means. (See Conformance (§2.4), which defines "·minimally conforming·" processors as those which cannot read schema documents in XML form, and "·schema-document aware·" processors as those which can.)" Alternative 2: (add a definition and use it) [DEFINITION:] A -serialized XML Schema Document- is an XML 1.x document corresponding to an XML -schema document- infoset. Then we can use something closer to the original text: "It is implementation-defined whether a schema processor accepts schema information in the form of -serialized XML schema documents- and/or in some other form that conveys the -schema document- Infoset. (See Conformance (§2.4), which defines "·minimally conforming·" processors as those which cannot read schema documents in XML form, and "·schema-document aware·" processors as those which can.)" A couple of other nits: I think references to schema document should hyperlink to the definition. Also, some reference to 4.3.1 might also be helpful, though I'm less sure about that. Thanks! Noah [1] http://www.w3.org/XML/Group/2004/06/xmlschema-1/structures.rq144.200607.html#infoset [2] http://www.w3.org/XML/Group/2004/06/xmlschema-1/structures.rq144.200607.html#key-schemaDoc [3] http://www.w3.org/XML/Group/2004/06/xmlschema-1/structures.rq144.200607.html#schema-repr
Received on Tuesday, 8 August 2006 22:21:18 UTC