On Wed, 10 Sep 2003, Anwar M. Haneef wrote:
I haven't been an active participant on this list, but have worked
on OPES for a while (2 years) from an academic standpoint. I agree
with Andre regarding the compactness of the rule expression
language. The reason for this is because I don't see the need for
these rules to be interepreted on the fly.
For the record: even if we decide that compactness is not important
for OPES applications, it is not a negative characteristic either.
On the other hand, Alex's proposed P language seems to entertain a
more flexible mechanism for expressing expressions. Maybe this is due
to my lack of experience in languages, but this is one major issue I
had with developing IRML-based Processing Point rules for content
delivery based on QoS and device characteristics.
Could you please post an example or two where IRML lacked expression
power you needed?
Another concern I had regarding P is the relative ease or complexity
of auto-generation P language rules. For instance, from my previous
experience (mentioned above), it is relatively simple to generate an
XML-based IRML rule by parsing a restricted clickable-web form that
allows users to define their preferences.
I assert that is it equally easy to generate IRML and P rules from Web
forms. Given a form that both languages can support, the code to
generate P or IRML statements would be virtually identical. With P,
the generator MAY perform additional optimizations and/or use
additional form entries, but that is a different story.
I guess most of these concerns boil down to my apprehensions
regarding the amount of expertise in the market with XML-parsers as
opposed to BNF parsers-generators. Should ease of development be a
criterion ?
I am not sure whether you are saying that there is more expertise with
XML parser generators. If you are, I strongly disagree. Parser
generators existed well before XML and are very well known. In fact,
most XML parsers are written using the knowledge gained from the good
old parsing theory.
Also, would it be possible to mix the features in IRML and P to
develop a mechanism by which structure could be defined by the
XML-based IRML while P syntax is used for expressions,
What would be the benefit of using XML then?
Alex.