RE: [boost] discrete_set class

From: Victor A. Wagner, Jr. (vawjr_at_[hidden])
Date: 2002-08-28 01:04:58

Just to set (pun intended) record straight.  I find the name "set" as used 
in the STL far outside any "set" concept I had before I encountered it 
(with the possible exception that you can add elements until you get 
tired...it has no pre-defined size)

At Tuesday 2002/08/27 10:31, you wrote:
>Rich,
>
>Mathematically it is obviously a set (although ordered), I was more
>worried about programmer's conception of a set, such as the STL set
>(which is not an unstructured set..), Pascal's set etc.

Any programmer coming from Pascal is already confused by the STL set which 
doesn't behave at all like a Pascal set.  This mimics Pascal set to an 
amazing degree, missing only the ability to unambiguously say "set of 
sometype".

>  All those
>concepts are open, in that any element of the correct type (where type
>is different from a simple, often short, enumeration) can be added.
>Thus, there is no "universal set" embedding all possible sets.
>
>Your construct does have a universal superset, and is in that case
>bounded (more than discrete, which holds for most (or all if you are
>bit-inclined) computer set concepts).
>
>Thus, your "discrete_set" type is more aligned with the "domain" and
>"constraint" concepts found in (Finite Domain) Constraint Programming.
>
>I do not want people to expect the common set properties

what do YOU consider common set properties?
I certainly never considered "find_equal_range()" to be a "common set property"

>  from your type,
>since your set is more of a "selection" (or constraint, if one prefers
>that nomenclature) of/on a finite "domain". If programmers get the right
>mindset, your type is an extremely valuable addition to Bosst.
>
>/David
>
>-----Original Message-----
>From: boost-bounces_at_[hidden]
>[mailto:boost-bounces_at_[hidden]] On Behalf Of spamjunk_at_[hidden]
>Sent: Tuesday, August 27, 2002 1:07 PM
>To: boost_at_[hidden]
>Subject: RE: [boost] discrete_set class
>
>
>David:
>
>Pardon my ignorance, as my degrees are not in math.  Other than a
>restriction on the element type, in what ways is this not a set.
>
>
>Regards,
>
>Rich Herrick
>
>
> > People are thinking about your construct as a set, which is "open" in
> > its nature.
> >
> > I suggested to borrow some terms and ideas from the area of Finite
> > Domain Constraint-solving. That proposal was apparently ignored, due
> > to the introduction of unknowns and overall whimsical appearance ;-)
> >
> > I think that using terms like "domain" or "finite_domain" with the
> > semantics from Constraint solving would clarify that this construct,
> > although being extremely useful, is not a regular "set".
> >
> > /David
> >
> > -----Original Message-----
> > From: boost-bounces_at_[hidden]
> > [mailto:boost-bounces_at_[hidden]] On Behalf Of
> > spamjunk_at_[hidden]
> > Sent: Tuesday, August 27, 2002 8:47 AM
> > To: boost_at_[hidden]
> > Subject: RE: [boost] discrete_set class
> >
> >
> > Ok, this is my fault.  As Joel has pointed out, I neglected to provide
>
> > documentation.  I apologize and will upload some as soon as I can.
> > For now, the problem with your examples is the class expects the
> > values of the elements to be in the range [LO, HI].  You are trying to
>
> > use values outside the range.  My understanding of C++ is that it is
> > undefined behavior to convert an int to an enum when it is outside the
>
> > enum's range.
> >
> > pop-server.stny.rr.com
> >
> > _______________________________________________
> > Unsubscribe & other changes:
> > http://lists.boost.org/mailman/listinfo.cgi/boost
> >
> > _______________________________________________
> > Unsubscribe & other changes:
> > http://lists.boost.org/mailman/listinfo.cgi/boost
>
>pop-server.stny.rr.com
>
>_______________________________________________
>Unsubscribe & other changes:
>http://lists.boost.org/mailman/listinfo.cgi/boost
>
>_______________________________________________
>Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

Victor A. Wagner Jr.      http://rudbek.com
PGP RSA fingerprint = 4D20 EBF6 0101 B069 3817 8DBF C846 E47A
PGP D-H fingerprint = 98BC 65E3 1A19 43EC 3908 65B9 F755 E6F4 63BB 9D93
The five most dangerous words in the English language:
               "There oughta be a law"