use Modern::Perl;

my $string = "
define('DB_NAME', 'blah');

/** MySQL database username */
define('DB_USER', 'blahbah');

/** MySQL database password */
define('DB_PASSWORD', 'blahblahblah');
";

my ($db, $db_user, $db_pass);

my $pre_regex = qr/^\s*define\s*\(\s*['"]/;
my $post_regex = qr/['"]\s*,\s*['"]([^'"]+)['"]/;
($db, $db_user, $db_pass) =
    map { ($string =~ /$pre_regex $_ $post_regex/mix || 'unknown') } qw(DB_NAME DB_USER DB_PASSWORD);


say $db;
say $db_user;
say $db_pass;