**From:** Herman Balsters (*h.balsters@bdk.rug.nl*)

**Date:** Mon 24 Feb 2003 - 13:35:17 GMT

**Next message:**Andrzej Wasowski: "Re: product types in OCL 2.0"**Previous message:**Gerrit Renker: "Re: product types in OCL 2.0"**In reply to:**Gerrit Renker: "Re: product types in OCL 2.0"**Next in thread:**Bauer, Robert: "RE: product types in OCL 2.0"

Gerrit, I don't think that there is any ambiguity in the definition of a->prod(b)->prod(c) The only way that you can read it is (a->prod(b))->prod(c) ( = (AxB)xC ) because a->(prod(b)->prod(c)) is syntactically not correct. Also, if you wish to represent Ax(BxC) then this can be done by a->prod(b->prod(c)) Do you agree? -herman On 24 Feb 2003 at 7:38, Gerrit Renker wrote: > Hi, > Sorry, the introduction of the Cartesian Product operator has escaped > me, my printed copy is still V1.5. I picked up a copy of the Version > 1.6 OCL 2.0 at > http://cgi.omg.org/cgi-bin/doc?ad/2003-01-07 (hope that this is the > current one). > > I can see a problem with this construct, it is ambiguous how > k-fold products for k>2 are defined. > > For example > a->product(b) : Set(Tuple{A,B}) > > is clear, but what about a->product(b)->product(c) ? > It might be read (1) as the Cartesian Product of three sets, > in which case the type might be: > a->product(b)->product(c) : Set(Tuple{A,B,C}) > > But the same expression can also be interpreted as (2) the product of a > binary Cartesian Product (AxB) with a set of class C elements: > a->product(b)->product(c) : Set( Tuple{Tuple{A,B},C} ) > > If as an example the 'x' operator from maths is used: > --the first case can be written as A x B x C > --the second case can be written as (A xB) x C > which is less ambiguous. > > Possibly such preference rules could be incorporated into the > definition? > > With kind regards > Gerrit > --- Jos Warmer <J.Warmer@klasse.nl> wrote: > Hi there, > > > > In section 6.5.1, page 6-10, the operation 'product()' is defined on > > Collection, resulting the carthesian product. > > You can write: > > > > > > collection->product(otherCollection) > > > > ===== > -- > Gerrit Renker Research Assistant > Constraints Group Computing Technologies Centre > The Robert Gordon University Aberdeen AB25 1HG > > __________________________________________________ > Do You Yahoo!? > Everything you'll ever need on one web page > from News and Sport to Email and Music Charts > http://uk.my.yahoo.com > > > > To remove yourself from this list please mail puml-list-request@cs.york.ac.uk > with a message containing the word "unsubscribe". > dr. H. Balsters Faculty of Business Science University of Groningen The Netherlands

**Next message:**Andrzej Wasowski: "Re: product types in OCL 2.0"**Previous message:**Gerrit Renker: "Re: product types in OCL 2.0"**In reply to:**Gerrit Renker: "Re: product types in OCL 2.0"**Next in thread:**Bauer, Robert: "RE: product types in OCL 2.0"