As far as an XSLT processor is concerned, there is no such thing as a
mis-spelt element in an XPath. If the XPath is syntatically correct,
then that is fine.

Consider a variation on the identity template that has a template that
matches on child::authr. you can run this against any input document,
whether validated or not. If you confine yourself to validated-only
documents, then some documents may be validated against schemas were
authr is a valid element name.

On 21/02/2008, Costello, Roger L. <costello@xxxxxxxxx> wrote:
> Hi Folks,
>
>  Consider this XML document:
>
>  <?xml version="1.0"?>
>  <Book>
>     <Title>My Life and Times</Title>
>     <Author>Paul McCartney</Author>
>     <Date>1998</Date>
>     <ISBN>1-56592-235-2</ISBN>
>     <Publisher>McMillan Publishing</Publisher>
>  </Book>
>
>  Here is an XPath expression to count the number of <Author> elements:
>
>     count(/Book/Authr)
>
>  Notice that Author has been accidentally misspelled in the XPath
>  expression.
>
>  The XML document conforms to this XML Schema:
>
>  <?xml version="1.0" encoding="UTF-8"?>
>  <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
>            elementFormDefault="qualified">
>     <xs:element name="Book">
>         <xs:complexType>
>             <xs:sequence>
>                 <xs:element ref="Title" />
>                 <xs:element ref="Author"  minOccurs="0"
>  maxOccurs="unbounded" />
>                 <xs:element ref="Date" />
>                 <xs:element ref="ISBN" />
>                 <xs:element ref="Publisher" />
>             </xs:sequence>
>         </xs:complexType>
>     </xs:element>
>     <xs:element name="Title" type="xs:string"/>
>     <xs:element name="Author" type="xs:string"/>
>     <xs:element name="Date" type="xs:string"/>
>     <xs:element name="ISBN" type="xs:string"/>
>     <xs:element name="Publisher" type="xs:string"/>
>  </xs:schema>
>
>  I executed the XPath using the non-schema-aware version of SAXON and
>  got the result: 0
>
>    That is what I expected.
>
>  Then I executed the XPath using the schema-aware version of SAXON and
>  got the same result.
>
>    That is NOT what I expected.
>
>  I expected SAXON to detect, by consulting the XML Schema, that Authr is
>  not a legal child of Book and generate an error at compile-time.
>
>  Note that this is a particularly troubling problem, since the XML
>  Schema declares the number of occurrences of the <Author> element to be
>  0-to-unbounded; thus, a result of 0 is a legitimate value and the
>  misspelling error may go undetected for a long time.
>
>  QUESTIONS
>
>  1. Is it the responsibility of a schema-aware processor to catch
>  misspelled tag names in XPath expressions?
>
>  2. Is there a flag that I can set in SAXON to tell it to catch such
>  misspelling errors?
>
>  3. Are there any XSLT/XPath 2.0 processors that will match such
>  misspelling errors?
>
>  4. Let me assume the answers to the three questions are No.  Then ...
>
>  4.1 Is there a way to redesign the XPath such that the misspelling
>  error would be caught?
>
>  4.2 Is there a way to redesign the XPath such that the misspelling
>  error would be caught, regardless of whether a schema-aware or
>  non-schema-aware processor is being used?
>
>  Thanks!
>
>  /Roger