2008/8/2 Michael Kay <mike@xxxxxxxxxxxx>:
>> Out of interest, does xml:lang annotate the input tree, or does the
>> lang() function walk the ancestor axis behind the scenes? Or
>> is it all implementation dependent?
>
> It's implementation-dependent, of course.
>
> Saxon walks the ancestor axis when you use the lang() function. I think it's
> used too rarely to be worth optimizing.

So (for Saxon anyway) doing:

test="lang('foo', .)"

is pretty much the same as:

test="ancestor-or-self::*/@xml:lang = 'foo'"

except that the lang() function should return true if the lang tested
is a subset of that declared in the attribute.

So given an existing proprietary solution that walks the ancestor axis
a lot, you're not going to gain anything by switching to xml:lang...

Cheers,
Wendell

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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
Mulberry Technologies, Inc.                http://www.mulberrytech.com
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