... copying the keys in advance isn't really efficient... My hopes were not to rely on dependencies...

I don't understand the point about real efficiency, but if you want absolutely no dependencies, you can always roll your own iterator. This one simply stops when it's exhausted, but it's easy to imagine simulating the behavior of the each built-in when it reaches the end of iteration. 

>perl -wMstrict -le
"my %hash = qw(
   one uno  two dos  three tres  four quatro  five cinco
   );
 sub my_each (\%) {
   my $hr = shift;
   my @k  = keys %$hr;
   ;;
   return sub {
     return unless @k;
     my $k = shift @k;
     return $k, $hr->{$k};
     }
   }
 ;;
 my $e1 = my_each %hash;
 my $e2 = my_each %hash;
 ;;
 print qq{e1: @{[ $e1->() ]}; @{[ $e1->() ]}.};
 print qq{e2: @{[ $e2->() ]} \n};
 ;;
 print qq{e1: @{[ $e1->() ]}; @{[ $e1->() ]}.};
 print qq{e2: @{[ $e2->() ]} \n};
 ;;
 print qq{e1: @{[ $e1->() ]}; @{[ $e1->() ]}.};
 print qq{e2: @{[ $e2->() ]} \n};
 ;;
 print qq{e1: @{[ $e1->() ]}; @{[ $e1->() ]}.};
 print qq{e2: @{[ $e2->() ]} \n};
"
e1: three tres; five cinco.
e2: three tres

e1: one uno; two dos.
e2: five cinco

e1: four quatro; .
e2: one uno

e1: ; .
e2: two dos

[download]

Update: Changed the code example slightly to clarify the termination behavior of the iterator.

In reply to Re^3: Indepedent lazy iterators for the same hash? by AnomalousMonk
in thread Indepedent lazy iterators for the same hash? by LanX

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