On Tue, 29 Oct 2002, Austin Hastings wrote:
: --- Piers Cawley <[EMAIL PROTECTED]> wrote:
: > >>
: > >> one(any($a, $b, $c), all($d, $e, $f))
: > >>
: > >> Is a good deal more intention revealing than the superficially
: > >> appealing than
: > >>
: > >> ($a & $b & $c) ^ ( $d | $e | $f )
First I would like to point out that the & and | are backwards there
from the original. & means all(), and | means any().
: Would it be practical/meaningful to say
:
: $result = bitwise ($a & $b & $c) ^ ($d | $e | $f);
: $result = superpose ($a & $b & $c) ^ ($d | $e | $f);
:
: And allow a use operation to select defaulting behavior? (With an
: appropriate warning if the code used one of these operators without
: specifying the use directive, even though <crab-style> is the default?)
All other things being equal, I think people will find modal operators
more confusing than if we just make separate operators.
That being said, I'm still wondering whether we can finesse it. Damian's
default any() semantics in numeric context select a random element. If
we made that not the default, we could have an alternate default semantics
in numeric (or, at least, integer) context. So suppose we introduce for
the "pick one" semantics an explicit verb named, oddly enough, pick().
my int $foo = pick( 1 | 2 | 4 ); # $foo gets (1,2,4)[rand 3]
my int $bar = 1 | 2 | 4; # $bar gets 7
People can be scared if they like, but I am also of the opinion that
superpositions are more "basic" than bitops, at least in a sense.
My reasoning for that is that they don't commit to an interpretation
prematurely. A 1 | 2 | 4 means "a 1, a 2, or a 4", nothing more.
You can make other things out of a superposition depending on the
context. Damian already made them mean two different things in numeric
vs string context. We could possibly make them mean more things.
So I wonder about whether, in
$result = superpose ($a & $b & $c) ^ ($d | $e | $f);
the "superpose" is really a no-op. If you go on to say
my int $foo = pick( $result ); # random element filling "contract"
my int $bar = $result; # bitwise
then the superposition would collapses as specified.
There is one little difficulty with this approach, though. It would
have to retroactively change the meaning of non-powers-of-two. That is,
if you say
$mask = 7;
$somebits = 1 | 2;
my int $foo = $somebits & $mask;
then at the point of wave-function collapse, the 7 from $mask has to
be re-interpreted as a 1|2|4. Maybe that's okay, and maybe it isn't.
>From a transactional view of QM, it's probably fine, since that view
allows for sending information back through time to entangled partners.
It's also fine from a tagmemics point of view, I think, since context
can change the meaning of both nouns and verbs.
Actually, I suppose that in contrast to int context, num context
could pick() by default. And str context could do strbitops.
Or it could do the currently specified str default of listing out
the whole shebang. That's probably more user-friendly when you print
out error messages, so I expect stringwise bitop collapse would have
to be requested explicitly. Or we need to have a bitstring type, or
some such. There are other places where distinguishing data strings
from human-readable strings would be useful.
Larry
