#!/usr/bin/perl 
    
use strict;
use warnings;
    
my @labels = qw /L0 L1 L2/;
        
while (<DATA>) {
    chomp;
    goto $labels[0];
  L0:
    if (/foo/) {
        print "FOO!\n";
        @labels = grep {$_ ne "L0"} @labels;
        next;
    }
    goto $labels[1];
  L1:
    if (/bar/) {
        print "BAR!\n";
        @labels = grep {$_ ne "L1"} @labels;
        next;
    }
  L2:
    print "$_ ";
}
print "\n";
   
__DATA__
one
two
bar  
three
four
foo
five
six 
foo
seven   
eight
bar
nine
ten  


one two BAR!
three four FOO!
five six foo seven eight bar nine ten