I did not have time before. Just a short example of a named closure (an iterator) at the command line:

$ perl -e 'use feature "say";
> {    my $number = 0;
>      sub supply_square {
>          $number ++;
>          return $number ** 2;
>      }
> }
> say supply_square for 1..5;
> say supply_square for 1..5; '
1
4
9
16
25
36
49
64
81
100
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