If there's a chance of wanting to catch bless'ed arrays, or dealing with psychologically nasty code, such as my $item=bless {}, 'ARRAY', then it's best to be paranoid and check if you can actually treat the item as an array.

The following code snippet shows a function that does this kind of check:

for my $item (@array) {
  print "We've got an array" if is_array($item);
}

sub is_array {
  my ($ref) = @_;
  # Firstly arrays need to be references, throw
  #  out non-references early.
  return 0 unless ref $ref;

  # Now try and eval a bit of code to treat the
  #  reference as an array.  If it complains
  #  in the 'Not an ARRAY reference' then we're
  #  sure it's not an array, otherwise it was.
  eval {
    my $a = @$ref;
  };
  if ($@=~/^Not an ARRAY reference/) {
    return 0;
  } elsif ($@) {
    die "Unexpected error in eval: $@\n";
  } else {
    return 1;
  }

}
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