$broken->{this} = $_ eq 'this' ? 1 : $broken->{this};
$broken->{that} = $_ eq 'that' ? 1 : $broken->{that};
$broken->{another} = $_ eq 'another' ? 1 : $broken->{another};
####
$broken->{$_} = 1 for @list;
##
##
my @valid = qw( this that another );
$broken->{$_} = 0 for @valid;
$broken->{$_} = 1 for @list;
##
##
my %valid = map { $_ => 1 } qw( this that another );
$broken->{$_} = 1 for grep $valid{$_}, @list;
##
##
my @valid = qw( this that another );
my %valid = map { $_ => 1 } @valid;
$broken->{$_} = 0 for @valid;
$broken->{$_} = 1 for grep $valid{$_}, @list;