On 2 Jun 2005, at 5:37 pm, Alberto Micol wrote:
>> Haven't heard any response to this message suggesting an alternative
>> means
>> of concatenating UCDs to permit their parsing by an XML parser.
>> Here's a
>> forward to make sure you all got it.
>>
>> No, we don't yet have UCD's operating under a schema, but we might
>> want
>> to some day and it will be much less painful if we make the switch
>> now.
>>
>> As far as I can tell, there's no obivous reason for the present
>> choice of
>> separator.
>>> Up until now, it hasn't been possible to check the syntax of a UCD
>>> list using
>>> XML Schema: there's no way (yet) to express a list of elements
>>> separated by
>>> semi-colons. This is a shame, since it means that somebody else has
>>> to do
>>> this work - work which could have been delegated to the XML parser.
>>>
>>> Fortunately, XML Schema recognizes lists of elements separated by
>>> white
>>> spaces, i.e. not
>>>
>>> "phot.calib;src.class"
>>>
>>> but
>>>
>>> "phot.calib src.class"
>>>
>
> I'm not an XML expert, hence please allow me a naive (if not stupid)
> question,
> to try to understand better your point.
>
> If we write a UCD with a blank as a separator, does that mean that we
> are
> going away from a simple string in favour of an array of strings/words?
>
> What impact will such change have on the VOTable standard?
The point is that the concatenation of UCDs in its present form (using a
semicolon) is effectively an array of UCD strings. The question is only
which character is defined as the separator. Since blanks are not
allowed
in UCDs, then a blank is as good a separator as a semicolon. Our
argument is that - from an XML perspective - blanks are MUCH BETTER
separators, since blanks permit us to check the syntax of a UCD entry
in principle whereas a semicolon-separated array of UCD strings looks
like a simple string to XML parsers.
The UCD standard is about to be made official - this is our opportunity to make a very small change with a very big effect.
Rick
Dr. Frederic V. Hessman Hessman-at-Astro.physik.Uni-Goettingen.DE Universitaets-Sternwarte Tel. +49-551-39-5052 Geismarlandstr. 11 Fax +49-551-39-5043 37083 Goettingen http://www.uni-sw.gwdg.de/~hessman ------------------------------------------------------------------------ -------------------------
http://monet.uni-goettingen.de ------------------------------------------------------------------------ -------------------------Received on 2005-06-02Z18:22:17