[ruby-talk:16600] Re: RCR: Enumerable: every() and none()

On Tue, 19 Jun 2001, Dennis Decker Jensen wrote:
> "Mathieu Bouchard" <[e-mail]> wrote:
> > def all? ; each {|x| return false if not yield x }; true ; end
> > def none?; each {|x| return true  if     yield x }; false; end
> 
> Yes, it is right.

No, it's not! ;-)

On Tue, 19 Jun 2001, Pete Kernan wrote:
> On Tue, 19 Jun 2001 02:22:59 +0900, Mathieu Bouchard pontificated:
> || def none?; each {|x| return true  if     yield x }; false; end
> ||
>                                ^                       ^
>                                false                   true

The one I wrote above is really "any?". I was thinking about "any?" when I
wrote "none?".

I'd prefer having "any?" than having "none?".



> For instance see [ruby-talk12330] and [ruby-talk:5017]
> I certainly would like to see the operators in the former suggestion :-)

The second suggestion [5017] was quite different. It was about quantum
superpositions. That is something originally written in Perl by Damian
Conway for YAPC 2000. (At YAPC 2001 he presented a quantum version of the
Game of Life, originally written by _John_ Conway) 

"any" and "all", in general, are ideas that can be applied in different
contexts. They can be methods returning true or false, like the above;
or applied to quantum superpositions, or goal-directed programming
(Prolog/Icon), which in those cases, make several values together act as
one.



matju