--- Moritz Lenz <[EMAIL PROTECTED]> wrote:

> Ovid wrote:
> > Anyone have any idea why Google is not indexing the official Perl 6
> > documentation at perlcabal.org/syn?  I checked the robots.txt and
> it
> > looks fine:
> > 
> >   http://www.perlcabal.org/robots.txt
> > 
> > But the search box on http://www.perlcabal.org/syn/ returns
> nothing.
> The whole domain seems to be missing from the index, not only the
> synopsis.
> If nobody else has any idea, I could get a webmaster account and try
> to
> find out what's wrong.
> > Specifically, I was looking for the documentation on how subsets
> work
> > as it looks like we can get declarative style constraint
> programming
> > for free:
> > 
> >   subset Crosshair of Point where { $_.inside_of($target_zone) };
> > 
> > Is that valid syntax?
> Yes. See http://perlcabal.org/syn/S02.html#Polymorphic_types for
> similar
> examples.

Well, looking at the examples that you and Jonathan listed, I see I
should refine my question.  For example:

  subset Crosshair of Point where {
      ?? $_.move_inside($target_area)
      :: $target_area.move_outside($_)

In other words, I think we could get proper constraint programming if a
subset can mutate its variable.  Otherwise, all assignment would need
to be wrapped inside of an eval and the code would be more bug-prone.

Will said mutating work?  If it does, all logic handling constraints
can be encapsulated in one spot.  On the other hand, this could lead to
mysterious action at a distance.  The losses are significant, but the
wins seem absolutely fascinating.


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