#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11139917
use warnings;

while( <DATA> )
  {
  my @pos;
  push @pos, @-, @+ while /\t+/g;
  @pos or @pos = (-1) x 2;
  print "@pos\n";
  }

__DATA__
foo bar baz
foo bar foo    baz ccc ddd
foo bar foo    baz ccc ddd    foo    bar    baz
foo bar foo        baz ccc ddd            foo
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