VOEvent - Param comment

[Tony Linde]

The reason that VOEvent and VOTable has stuff like <param> tags and the like
(and VOTable has a lot worse) is because they are dead-end technologies.
They cannot be used for anything except being looked at by humans (possibly
mediated by pretty graphics). If they were used in downstream applications
(by people other than those creating the standards) they would cause errors
and failures and would return false data and so would not have come into
existence or would have been replaced before getting ratified.
 
The problem will come when people do want to use them to do something useful
(Rob's V2) because the argument will be that everyone now knows the format
(except, like VOTable, everyone will interpret it differently) and so it
cannot be changed so stuff will be bolted on the side to try and make it
work - like the utype in VOTable to take account of data models (which is
the most daft fudge I've seen in over 30 years of development) . And, of
course, that will simply cause even more problems and errors downstream.
 
This is nothing to do with pragmatism - the schema approach is the more
pragmatic - nor to do with ease of development - as Petr has said, the
schema approach is the easier to develop, but only to do with what *looks*
easy.
 
Yes, I know I've said all this before but at least this reiteration might
save Petr wasting his breath and time trying to convince people otherwise.
 
I will say that at least VOEvent does have its core data in properly tagged
elements: the param data is useless for downstream processing but at least
the core information can be used - unfortunately the same cannot be said of
VOTable where none of the data can be used downstream with any certainty.
(But I fully expect sometime in the future for someone to want to add the
utype attribute to the param tag making VOEvent just as bad as VOTable.)
 
T.
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