[tei-council] note in sourceDesc

[Sebastian Rahtz]

> 
> "Suppose, however, that an XPath-valued @context attribute were 
> available on any of the elements
> <elementRef>, <macroRef>, or <classRef> restricting its applicability. 
> Thus, the content model for <p> might say something like
> 
> <elementRef key="s" context="ancestor::text" minOccurs="1"/>
> <macroRef key="macro.limitedContent" context="ancestor::teiHeader"/>
> 
> to indicate that a <p> within a <text> element must contain one
> or more <s> elements only, whereas one within a TEI Header must
> use the existing macro definition limitedContent".

It's a fair cop :-)

I wish I had any idea how to start with implementation of this.

Sebastian