Re: are all strings in a sequence valid potential QNam

I think, this has been a great discussion. I completely missed the
special case of "castable as" for xs:QName.

I learnt (I've gone back to my memory lane :)) from Ken's post, that
lexical & value space of xs:QName is different. The value space of
xs:QName checks for a URI, and "castable as" works on a value and not
on lexical representation.

As has been told, "castable as" is not correct for this use case. As
Mike suggests, I'll also go for a regex solution.

On Thu, Feb 4, 2010 at 11:10 AM, Michael Kay <mike@xxxxxxxxxxxx> wrote:
>
> Just to check that by "valid potential QName" you mean a string that is in
> the lexical space of xs:QName and will therefore constitute a valid QName
> provided the prefix is in scope?
>
> ($x castable as xs:QName) will not work because (a) it also tests whether
> the prefix is in scope, and (b) to avoid the issues of it therefore being
> context-sensitive, the W3C spec says this is only allowed if the argument
> ($x) is a string literal.
>
> So you do need to use the regex approach.
>
> Regards,
>
> Michael Kay
> http://www.saxonica.com/
> http://twitter.com/michaelhkay



-- 
Regards,
Mukul Gandhi