There has been a lot of discussion in the other threads lately about
iterators. I was wondering if there will be an easy way to create a
bidirectional iterator? Toy example to show what I'm thinking:
for(1..10) {
next if /7/; # always skip 7
prev if 9 && !rand 3; # occasionally backup and redo 8
print;
}
More significant example:
class BigNum is Iterator:bi
{
has [EMAIL PROTECTED] is Iterator:bi;
...;
method postfix:*=($arg) {
my @temp is Iterator:bi;
my $carry = 0;
for ([EMAIL PROTECTED]:last_to_first) {
my $num = $_ * $arg + $carry;
my $val = $num % 10;
$carry = int( $num / 10 );
unshift @temp, $val; # efficient because it's a bi Iter
}
[EMAIL PROTECTED] = @temp;
}
};
Sometimes an iterator cannot be bidirectional--for example, reading
from STDIN--but that's fine; not all iterators need to be. And yes,
if I want a linked list, I can use a module off the 6PAN, or write it
myself, but that involves objects and methods. That's a lot of
conceptual overhead for something that may be quite simple.
--Dks
--
[EMAIL PROTECTED]
