use v5.14;
use warnings;

{
  package _csv;			# some package name

  our $row;
  our $col;

  sub c {
    my $c = shift // $col // die "col undefined";
    my $r = shift // $row // die "row undefined";
    say "c:$c r:$r";
  }

  say "--- inside same scope";
  for $row (1..3) {
    c("A");
  }
}

package main;

BEGIN { *c = \&_csv::c } # fake import for demo

say "--- one default";
for $_csv::row (1..3) {
  c("B");
}


say "--- two defaults";
for $_csv::col ("C".."D") {
  for $_csv::row (4..5) {
    c();
  }
}


say "--- explicit local ";

{
  local $_csv::row = 10;
  c("E");
  c("F");
}


say "--- defaults were localized inside loop";

c("G");