Erik Sundvall wrote: > Hi! > > > Actually I would prefer more emphasis on the view that the AM is the > main reference and that ADL is a serialization of it. But a "reference > form" of individual _archetypes_ needs a serialization not just an > object model of course... > The AOM is indeed intended as the definitive model of an archetype. However it is currently lacking in a few small areas - the ARCHETYPE_ONTOLOGY class needs some additional items for example. But in terms of explanatory power, object models are often not the best representation; they show a parser-output view. Syntax shows a parser-input view, and we humans are parsers (i.e. we read things serially). This is why we represent mathematics, java code, OWL, EBNF and many other things in the form of syntax.
By definition, an syntax is a 'serialisation' of its object model. But I don't think we can see all syntaxes as being the same. There is an OWL-RDF syntax for OWL, but it is unreadable gibberish, so humans usually read OWL-abstract. Similarly, Java programmers use the Java language rather than some XMI-like syntax. Syntaxes designed primarily for data serilialisation are not necessarily any good for human use, including comprehension, explanation of principles and therefore education. Most XML is of the latter kind - a direct serialisation of some object model. But you can't read it and understand it in the way that you can an abstract syntax (if anyone doubts this, just try reading OWL-RDF or XMI sometime). > No matter how nice and pure ADL might be, I have seen people getting > suspicious of "this OpenEHR-thing" when ADL has been focused too > strongly. (Or people getting upset by having to learn yet another > language, alternatively having been put of by the idea of having to > write an ADL parser in a new environment.) It's wonderful that there > are now two "official" ways (ADL and XML) to serialize AM constructs, > having even more would probably not hurt. > there are also at least 2 open source parsers available. In an ideal world we would have just used an existing language, but none of the candidates proved up to the job. OWL probabaly comes closest., but still lacks some basic constructs that prevent it being easily usable for archetypes. The power of ADL is important to me now as I am in the midst of defining extensions and semantics for specialisation. I originally thought I would do it directly as an object model, but found I had to go back to ADL to understand the semantics properly; changing / enhacing object models will come as a largely derivative step. > Thomas Beale wrote: > >> Interesting links: >> http://www.json.org/xml.html >> > > For some months I have been wanting to experiment with making a simple > JSON implementation of the AM (and eventually also the RM) as a > compact javascript- and Flash/Flex-friendly alternative to ADL/dADL > and then submit it as an ITS for openEHR. I realize I won't have the > time for it though so I drop the idea here hoping that someone else > gets inspired. > > I think this is an excellent idea, and it would make a very useful ITS. - thomas beale
