my @array = qw/ foo bar baz blah bar blah baz/;

my $save = 0;
my %done;
for (my $x = 0; $x <= $#array; $x++) {
  $save = $x if ($array[$x] eq 'bar'  );
  print "X:$x SAVE:$save $array[$x]\n";
  if ( $array[$x] eq 'blah' and !defined($done{$x}) ) {
    $done{$x}++;
    $x = $save;
  }
}