On Sat, May 07, 2005 at 05:11:19PM +1000, Stuart Cook wrote:
: On 5/7/05, Patrick R. Michaud <[EMAIL PROTECTED]> wrote:
: > It might not be a problem -- I'm thinking we may end up tokenizing
: > most or all of the meta operators, so that [+] would be considered
: > its own token, and then the "longest matching token" rule
: > would be sufficient to disambiguate the terms:
: > 
: >   $x = [+1, -2, +3]; # token [ indicates a term
: >   $y = [+] @stuff; # token [+] indicates a meta-op prefix operator
: Does that mean postfix meta-ops that modify syntax become possible?
: (Not necessarily a good idea, mind you, but possible...)

Vaguely.  One could imagine for instance a hyper variant that says
"do this to yourself", and this could force interpretation of the preceding
operator as an infix operator rather than a unary.  So despite the
fact that there's a unary *, this

    @squares = * @list;

could be the same as

    @squares = @list * @list

I'm inclined to agree that it's not a terribly good idea to have
a metaoperator that does retroactive violence to the meaning of
an operator.  (Note that + doesn't actually change the meaning of
the +.)

On the other hand, since we've distinguished hyperops on infixes from
hyperops on unaries, maybe an infix hyperop in unary position just
does the thing to itself:

    @squares = * @list;

which gives us a sum-of-squares that looks like this:

    @sumofsquares = [+] * @list;

That's...interesting...and it doesn't retroactively change the meaning
of *, since it's got the  out front, which currently has no meaning
when a term is expected, unless I'm going completely senile.  Every day
it gets a little harder to distinguish my senility from my insanity...


Reply via email to