Use dynamic variables. And then localize them in the sub doing the calling. Using variables names that start with :: will force them into main. 

sub exec_callback {
   my $code=shift;
   local $::hash={};
   local $::row=1;
   $code->();
}

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This is basically all that happens with $_ or $a and $b in a sort routine or map or File::Find or Scalar::List::Utils. $a and $b are declared "special" so there shouldnt be any conflicts with them. Using $main::hash ($::hash) might have the potential for conflict.

---
$world=~s/war/peace/g

In reply to Re: Need an $a and $b as in perl's sort routine by demerphq
in thread Need an $a and $b as in perl's sort routine by rational_icthus

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