Re: [xsl] Timezone concept broken in XPath 2.0?

Subject: Re: [xsl] Timezone concept broken in XPath 2.0?
From: Michael Ludwig <milu71@xxxxxx>
Date: Mon, 10 Nov 2008 13:22:01 +0100
Deborah Pickett schrieb am 10.11.2008 um 22:56:30 (+1100):
> Michael Ludwig wrote:
> > [...] I haven't yet encountered a system that doesn't do local time
> > and makes this functionality available to applications.
> I think that this is the root of our differing opinions.  I'd buy your
> argument if we restricted ourselves to "fat" operating systems like the
> general-purpose commercial or open-source ones that you name.  On such
> systems, the XPath runtime can delegate time zone computations to the OS
> (essentially the set of known time zone names becomes part of the
> context of the expression).  The amount of work needed to be done by the
> XPath processor is pretty small.
> What I don't buy is the assumption that XPath is always going to run on
> such "fat" platforms.  XPath is useful in embedded situations that might
> have no reason to know about time zones.  Consider an SVG renderer built
> into a printer.  Or a network router with its config files stored as XML
> (my router does just that).  Such implementations need not even have a
> real-time clock.  For them, having to implement XPath 2.0
> fn:adjust-dateTime-to-timezone() is an imposition, but not a huge one.
> The function is, after all, just glorified arithmetic in a weird base.

Hi Deborah,

this is true, and a good objection. I hadn't thought about such small
systems that aren't even fully time-aware. And it's true that the
adjust-*-to-timezone functions are purely arithmetic, so even such small
systems can implement them.


Michael Ludwig

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