my @all_keywords = (qw(one two three )); my @mandatory_keywords = (qw(two three )); my $source1 = q{ONE="xyz\t" two=a_34 three = 'name="O\'Hara"' }; my $source2 = <<'END'; two=a_34 three = 'name="O\'Hara"' ONE="xyz\t" END