[SCL] SCL vs. Z(ed)

[Harry Delugach]

Another followup to Pat's note:

>> ACTION ITEMS:
>> - examine other standards that may overlap CL, especially the Z 
>> standard (ISO/IEC 13568) which has been recently approved. There is 
>> concern that Z (pronounced "zed") has already standardized a form of 
>> logic. I have a copy of that standard for anyone who is interested.
>
> We have examined that, at John's suggestion. It has very little to do 
> with SCL, either in its aims (Z is aimed at proving properties of 
> programs, not ontology development) or its syntax (Z syntax is highly 
> idiosyncratic) or its semantics (Z is not a first-order language),and 
> I have seen no evidence of Z being used in any of the likely use 
> groups or user communities for the SCL standard (database technology, 
> description logics, ontology development, semantic web, AI-KR).  I 
> have heard the "concern" you mention expressed only by John Sowa: 
> until I hear evidence of its being a general concern, I am not 
> inclined to pursue the matter in any more detail. The issue was not, 
> apparently, raised at the presentation given in Santa Fe in January.

The concern has been mentioned to me by two vocal and influential 
members of L8 (the US contingent) within the past week. Consider it 
evidence of "concern" even though they may be more political than 
technical. If you have good technical arguments as to why Z is not 
comparable to SCL, that's great! Those arguments need to be written up 
and included as an informative annex to the draft. I've been assured 
that someone will bring it up at the meetings, so having written 
arguments already in place will speed up resolution of these comments. 
The reason is that ISO wants to be sure that SCL is not another version 
of Z. However, it is also likely that some of the definitions in the Z 
spec, some of the set operations, etc. can be used by reference in the 
SCL draft. If so, that is a good thing -- ISO likes to see parts of its 
standards re-used in other standards.

For the record, I've seen Z used as a requirements specification 
language in many places, it is not just a software language. It is 
really meant to specify systems. Also the fact that the communities you 
listed aren't using it NOW, doesn't mean they won't be using it soon, 
perhaps in frustration at the lack of SCL's progress. Remember that Z 
is already a standard (ISO/IEC 13568:2002) and people who want to use a 
standard may not be willing to wait four or five more years to 
penetrate a market, even if the standard doesn't address all their 
needs.

Harry