> On Tue, Aug 01, 2000 at 11:59:22AM -0400, Chaim Frenkel wrote:
> > Reduce (e.g. $x = reduce { sum } @list;
>
> I mentioned this to Larry on the Friday after the conference
> and his response was that he did think about it originally but
>
> $sum = reduce + @list; # assuming I got the verbal->syntax translation right
>
> was not easy todo. I was not even thinking of that but just some like
> sort where we have $a and $b (ala the List::Util::reduce function)
> But I must admit, this syntax would be nice for some operators
I had a paper on that.
The solution (which I with RFC RSN) is to provide a simple mechanism for
generating higher-order functions.
The one I proposed in the switch statement paper
(http://www.csse.monash.edu.au/~damian/TPC/2000/switch/paper.txt) was
the __ meta-variable. Used in place of an operand or an argument, it
creates an anonymous subroutine that evaluates the corresponding
operation or subroutine, substituting elements of @_ for the
meta-variables.
In other words:
$incr = __ + 1;
is exactly equivalent to:
$incr = sub { $_[0] + 1 }
So you can additively reduce a list like so:
$sum = reduce __+__, @list;
There's a protoype implementation available as part of the switch.pm module,
which will hit the CPAN some time this week (assuming I don't actually
*die* of jet-lag :-)
Damian
