Re: exclude-result-prefixes required in each imported

> You set it for each individual stylesheet module.
true, but I dodn't see the arguments for that behaviour as clearly black
and white as you describe.

> This means that the source text can be understand in terms of itself, plus 
> any texts it depends upon (via xsl:include or xsl:import).
Not necessarily, the module may be affected by higher priority variable
and template definitions and xsl:output attributes etc.

> If instead, the importing modules settings were used, then you would need to 
> read the set of all modules that depend upon the txt you are reading - a 
> potentially unbounded set - many of it's members might not yet be written.

That's the case already, if a stylesheet module uses $foo and doesn't
have a definition of a variable foo (or even if it does) then if you
need to find foo you need to find the stylesheet (or sheets) that import
this. (Which makes separate compilation interesting no doubt:-)

> So this would be a very bad software engineering practice. Fortunately, the 
> XSLT designers didn't do it  that way.

But most comparable features of xslt _do_ work that way.

David