- From: Alexander Falk <al@altova.com>
- Date: Thu, 1 Nov 2001 10:22:25 -0500
- To: <Noah_Mendelsohn@lotus.com>
- Cc: <ht@cogsci.ed.ac.uk>, <mfeblowitz@frictionless.com>, "XML Spy Support Team" <support@xmlspy.com>, <xmlschema-dev@w3.org>
Noah, My concern wasn't about what we already do in Spy, which - I agree with you - is totally conforming to the specs. The suggestion from Mark was to allow different development-time and runtime mechanisms for importing schema components, which would allow a user to do this: At development time: A.xsd CommonTypes.xsd B.xsd CommonTypes.xsd At runtime: Umbrella.xsd CommonTypes.xsd A.xsd B.xsd In other words, have a special development-time-only import mechanism that would allow a schema development environemnt, like XML Spy, to fetch the schema components from CommonTypes.xsd whenever A.xsd or B.xsd are being edited, but those would be different from the standard xs:import that would be used at runtime by schema-aware validating parsers, so that at runtime the CommonTypes.xsd would only be imported once from some Umbrella.xsd schema document. With respect to that suggestion, my comment was that we would certainly put this on our wishlist, but would be reluctant to invent a mechanism for Spy alone. However, if we as the XML Schema WG would come to the conclusion that this is something to think about for Schema 1.1 or 2.0, and there was a standard W3C-endorsed way of distinguishing between development-time and runtime imports, then we would certainly proceed to support this in XML Spy. As of now, however, the burden is certainly on the implementors of schema-aware parser's to support the currently endorsed mechanism, which does not differentiate between development time and runtime inclusion, and thus must support this scenario: At development time: A.xsd CommonTypes.xsd B.xsd CommonTypes.xsd At runtime: Umbrella.xsd A.xsd CommonTypes.xsd B.xsd CommonTypes.xsd And thus it is the job of other parser implementors to do what we have done: to detect such multiple inclusions and process them correctly, like any C/C++ or other compiler do it, too. And you are, of course, correct in your assertion that we need to track a URI and filename list for this purpose. If components are acidentally the same, this is an entire different story. All we resolve, is multiple inclusions or import that reference the same file or the same URI in their namespace. Best regards, Alexander ... Alexander Falk ... President & CEO ... Altova, Inc. - The XML Spy Company ... Member of the W3C Advisory Committee ... Member of the W3C XML Schema Working Group =================================================================== XML Spy 4.0 Suite: the original award-winning IDE, Document Editor, XSLT Designer, Browser Plug-In, XML Schema Editor, and B2B Server Visit www.xmlspy.com to download your free evaluation copy today! =================================================================== The information transmitted in this message and/or as an attachment to it is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer. Altova GmbH and Altova, Inc. do not accept legal responsibility for the contents of this message. Any views or opinions presented are solely those of the author and do not necessarily represent those of Altova GmbH and Altova, Inc. unless otherwise specifically stated. Thank you! -----Original Message----- From: Noah_Mendelsohn@lotus.com [mailto:Noah_Mendelsohn@lotus.com] Sent: Wednesday, October 31, 2001 21:42 To: Alexander Falk Cc: ht@cogsci.ed.ac.uk; mfeblowitz@frictionless.com; XML Spy Support Team; xmlschema-dev@w3.org Subject: RE: Schema being imported multiple times Alexander Falk writes: >> But as long as there is no standardized >> (i.e. W3C-endorsed) way of doing this, The schema spec requires that you not include conflicting definitions or declarations for the same component. If you know from your runtime that you are in fact about to open the same file you just parsed, then it's clear you're getting the same definitions and decls (unless I'm missing something subtle). So, I believe that the schema spec does sanction your using any means you can that will ensure consistent definitions and declarations. If you keep a filename or URI list, I think you are OK. What is not in general efficient is looking for duplicates when importing files or web resources that are accidently the same, I.e. ones for which the names or URIs are different, but the contents are the same or consistent at the component level. That you have to check the hard way, but that is a rarer case I would think. ------------------------------------------------------------------------ Noah Mendelsohn Voice: 1-617-693-4036 Lotus Development Corp. Fax: 1-617-693-8676 One Rogers Street Cambridge, MA 02142 ------------------------------------------------------------------------
Received on Thursday, 1 November 2001 10:22:30 UTC