xml-dev - Re: Inserting optional elements

[james anderson <james.anderson@mecomnet.de>]

"List-valued" entities are much easier to operate on if one required the
elements to have identifying attributes. By "list-values" I mean any
content where the element names are not sufficient to describe an
unambiguous access path. We couldn't see any reason to support "blind"
operations on an elements by position only. It doesn't even have to be a
true id attribute - just among the siblings.

Matthew Gertner wrote:
> 
> Paul,
> 
> This is an good point. XPath is not sufficient to specify the location of a
> new element unambiguously. This is obvious from the following example:
> 
> <element name="foo">
>         <complexType>
>                 <element ref="bar" maxOccurs="unbounded"/>
>                 <element ref="baz"/>
>                 <element ref="bar" maxOccurs="unbounded"/>
>         </complexType>
> </element>
> 
> Suppose I have the following document:
> 
> <foo>
>         <bar/>
>         <bar/>
>         <baz/>
>         <bar/>
> </foo>
> 
> If I want to add an element with the XPath "foo/bar[3]", then I have no way
> of knowing whether this will result is bar,bar,bar,baz,bar or
> bar,bar,baz,bar,bar. This is only one of several problems with XPath. We're
> thinking about extending the standard to solve these problems, so I'd be
> most interested to know if any other individuals, companies or organizations
> are working on this and want to collaborate. I haven't checked whether the
> W3C is working on this yet (but I will).
>