On Tue, Nov 05, 2002 at 11:36:45AM -0500, Ken Fox wrote:
: Jonathan Scott Duff wrote:
:
: >Um ... could we have a zip functor as well? I think the common case
: >will be to pull N elements from each list rather than N from one, M
: >from another, etc. So, in the spirit of timtowtdi:
: >
: > for zip(@a,@b,@c) -> $x,$y,$z { ... }
:
: sub zip (\@:ref repeat{1,}) {
: my $max = max(map { $_.length } @_);
: my $i = 0;
: while ($i < $max) {
: for (@_) {
: yield $_[$i]
: }
: ++$i
: }
: return ( )
: }
:
: That prototype syntax is probably obsolete, but I'm not sure
: what the current proposal is. It might be better to force scalar
: context on the args so that both arrays and array refs can be
: zipped.
You never have to put \ into a signature anymore--that's the default.
You only get list context (and flattening) when you use the splat.
For a recurring scalar context, you want something like:
sub zip (@refs is repeatedly (Array)) {
The exact syntax is subject to change, of course.
: I really like the idea of using generic iterators instead of
: special syntax. Sometimes it seems like we're discussing 6.x
: instead of just 6.0.
:
: This iterator is nice too:
:
: sub pairs (\@a, \@b) {
: my $max = max(@a.length, @b.length);
: my $i = 0;
: while ($i < $max) {
: yield @a[$i] => @b[$i];
: ++$i
: }
: return ( )
: }
:
: for pairs (@a, @b) {
: print .x, .y
: }
Neither of these work on arrays which have a finite but unknown length.
Larry
