Is-a (was-a Re: [xml-dev] Victory has been declared in the schema wars ...)

Richard Salz said:
>>   <pattern is-a="RequiredChild">
>
> Why 'is-a'?  Why not something already common, like id or name?  Then I
> could easily expect to use the fragment notation to fetch a pattern, or
> reference it within a namespace URI.

The pattern can have a name attribute to give it an id. I left them out of
the examples for clarity.

The is-a attribute connects the pattern to an abstract pattern declaration
with the same name. So in the example above there would be something like
  <pattern name="RequiredChild" abstract="true">
     <rule context=" $parent ">
        <assert test=" count( $child ) &gt;= 1 ">
        In a <name/> element, the element <name select=" $child "/> is
required.
         </assert>
      </rule>
   </pattern>

Cheers
Rick Jelliffe