<div dir="ltr"><div>Markus,<br><br></div><div>re: extracting the ivoa model from the vo-dml document.<br></div><div> This suggestion has come up multiple times for various reasons, and I think it has been <br> generally considered a good idea, or at least not a bad idea.. but hasn't had sufficient <br> momentum to become an action item. I think we may be there now.<br><br></div><div> The mail you refer to, and example serialization also depend on an addition/change to <br> the ivoa model if this alternate modeling is considered the right approach.<br></div><div><br></div><div>re: use of 'ivoa' types in annotation.<br></div><div> The ivoa types model serves to provide a common type set for models.<br></div><div> What goes into the LITERAL tag in the annotation is a topic for the Mapping syntax.<br></div><div> I expect the reasoning for using the ivoa type in the annotation is to provide consistency<br></div><div> when interpreting the annotation. Regardless of the serialization format, interpreting the <br></div><div> content is the same... and based on the vo-dml ids.<br></div><div><br></div><div> I'll let the Mapping people talk more to that though.<br></div><div><div><br></div>Mark<br><br><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Apr 11, 2017 at 9:57 AM, Markus Demleitner <span dir="ltr"><<a href="mailto:msdemlei@ari.uni-heidelberg.de" target="_blank">msdemlei@ari.uni-heidelberg.<wbr>de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear DM,<br>
<br>
I feel mildly bad for bringing another issue up, in particular since<br>
it really concerns VO-DML, and that this late into its RFC. But it's<br>
the kind of thing you notice when you start to play with stuff, and<br>
in this case it's also because of the new annotation scheme showcased<br>
by Mark in his mail<br>
<a href="http://mail.ivoa.net/pipermail/dm/2017-April/005519.html" rel="noreferrer" target="_blank">http://mail.ivoa.net/pipermail<wbr>/dm/2017-April/005519.html</a>. I've made<br>
a corresponding note on the RFC page<br>
<a href="http://wiki.ivoa.net/twiki/bin/view/IVOA/VODML1RFC" rel="noreferrer" target="_blank">http://wiki.ivoa.net/twiki/bin<wbr>/view/IVOA/VODML1RFC</a>, but since most of<br>
you probably won't see it there, I take the liberty of copying it<br>
here:<br>
<br>
[With Mark and Tom's proposed serialisation I] noticed that with it<br>
the types in the ivoa: DM that is part of the VO-DML spec become<br>
actually relevant outside of the lofty heights of drawing diagrams:<br>
VOTable writers will have to infer them for writing LITERALs.<br>
<br>
Only then did I realise that ivoa: really defines another type<br>
system. Now, DaCHS already translates between a gazillion type<br>
systems (among others, postgres, python, TAP, VOTable, FITS, numpy,<br>
XSD). Based on this, you could say it doesn't really matter.<br>
<br>
But another type system still is another source of bugs, impedance<br>
mismatch ("oh boy, what do I translate rational into?"), and<br>
annoyance for our users ("What, LITERAL has a dmtype attribute that's<br>
using something that has nothing to do with PARAM's @type?"). Is it<br>
really, really, really necessary that ivoa: does not just re-use the<br>
VOTable type system?<br>
<br>
Since a thorough investigation of this matter might slow down the<br>
RFC: How difficult would it be to pull the ivoa: DM out of VO-DML and<br>
have a document of its own for it? That'd also give us a bit more<br>
time to think about Quantity; also, I think our future selves will be<br>
grateful if they don't have to re-issue VO-DML itself when they just<br>
want to fix ivoa:...<br>
<span class="m_5558673671611692421HOEnZb"><font color="#888888"><br>
-- Markus<br>
</font></span></blockquote></div><br></div></div></div></div></div>