Re: proposed: use abstract syntax notation (asn06)

I agree 100% with Gerd's point - and Sandro. RIF is not about concrete
syntax, it is about abstract syntax (Please refer to POINT C in ACTION-87
http://lists.w3.org/Archives/Public/public-rif-wg/2006Oct/0083.html.
We need to define classes and attributes, and API- that sort of things
- not any particular surface syntax. Isn't this the *very need* for
a RIF? Viz., *interchange* of *disparate concrete surface syntaxes*
through a *common AST format* called ... the *Rule Interchange Format*,
a.k.a. RIF! :-)

I also agree (again) with Franck McCabe. As I wrote in the above
cited reference:

>    I personally think that the RIF should not be a J.A.R.L. and this
>    for the follwing reasons:
> 
>    1. The RIF, being an Rule *Interchange* Format purporting to support
>       interoperability among rule languages, is a formalism for
>       expressing all the essential concepts making up rules and rulesets
>       that need to be represented. As I tried to explain in my original
>       quote from Peter Landin's "The Next 700 Programming Languages"
>       (and as Frank McCabe recently reminded us), the RIF is a language
>       space in which specific (rule) languages are to be mapped.
> 
>    2. Such mappings are typically realized by parsing some RL's specific
>       *concrete* surface syntax into an *abstract* syntax representation
>       using elements of a RIF ontology. Such an abstract syntax is the
>       closest one may speak of "syntax" when sepaking of the RIF. Indeed,
>       by *RIF syntax* one should not mean human-readable syntax, but
>       some representation thereof based on a consensual vocabulary.
> 
>       Importantly, such an abstract syntax, contrary to usual concrete
>       syntax,
> 
>          (a) is non-linear (i.e., it is tree- or graph-based);
> 
>          (b) is not human-readable (i.e., it will be XML-based);
> 
>          (c) has well-defined semantics allowing one or several
>              operational interpretation;
> 
>          (d) must be consensual (unlike concrete syntaxes that
>              can me mapped into a RIF-compliant AST).

My 2 cents,

-hak

Gerd Wagner wrote:

>>I think what you are trying to define is an ontology for rule parts
>>(or maybe a UML-like diagram). This is fine and useful, but I 
>>don't think it is a substitute for a concise BNF. 
> 
> 
> Sandro is right with observing the insufficiency of EBNF 
> as compared to MOF/UML, which is a bit more abstract (e.g. 
> in its way not to imply any order of expression components)
> and more expressive, e.g., by clearly distinguishing between
> references and components and by allowing to attach 
> contraints to syntax elements, while at the same time
> providing more readable syntax definitions.
> 
> As OWL 1.1 is following R2ML (www.rewerse.net/i1) in using 
> MOF/UML for the abstract syntax definition (although, 
> probably since they are still a bit unexperienced, they 
> are making a few mistakes such as using the white diamond
> instead of the black diamond for composition, or not
> suppressing the visbility symbols), RIF should also follow
> this move and make both a MOF language model and an EBNF
> grammar, instead of trying to reinvent the wheel with 
> developing some other (non-standard) method.
> 
> In the REWERSE project, several working groups (not just I1)
> have choosen MOF/UML as the abstract syntax definition
> language that can be complemented with EBNF.
> 
> -Gerd
> 
> 
> 
> 


-- 
Hassan Aït-Kaci
ILOG, Inc. - Product Division R&D
tel/fax: +1 (604) 930-5603 - email: hak @ ilog . com

Received on Sunday, 12 November 2006 13:33:54 UTC