OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help



   Re: XPath and XSD/RNG

[ Lists Home | Date Index | Thread Index ]
  • To: xml-dev@lists.xml.org
  • Subject: Re: XPath and XSD/RNG
  • From: "Robert C. Lyons" <boblyons@unidex.com>
  • Date: Wed, 01 Jun 2005 20:23:04 -0400
  • Cc: stefan.tilkov@innoq.com
  • In-reply-to: <1117657238.3338.ezmlm@lists.xml.org>
  • References: <1117657238.3338.ezmlm@lists.xml.org>
  • User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.2) Gecko/20040803

Stefan Tilkov wrote:
    "Is there a way to check whether an XPath expression could possibly be 
    true for a document conforming to a particular W3C XML Schema (or 
    Relax NG schema) without having access to the document? Is this 
    something that toolkits support?

    E.g. if the schema disallows /root/element/subelement, the XPath 
    expression /root/element/subelement[0] cannot yield a non-null result 
    for any conforming document."


It's not possible to write a general algorithm that determines
whether or not an XPath expression could possibly be true
for all documents that conform to a schema. This problem is
undecidable. Also, the problem of whether or not an XPath
expression is satisfiable is undecidable.

For more details, please see:


Best regards,

Bob Lyons
XML and Java Consultant


News | XML in Industry | Calendar | XML Registry
Marketplace | Resources | MyXML.org | Sponsors | Privacy Statement

Copyright 2001 XML.org. This site is hosted by OASIS