use experimental 'refaliasing';
my $rvars = { foo=>"bar" };
\my %vars = $rvars;      # alias
print $vars{foo}, "\n";  # prints "bar"
$vars{abc} = "xyz";      # modifies $hashref's contents

##</code><code>##

use Path::Tiny;
use Time::Piece;

my $ref_var = {
	abs => path(__FILE__)->absolute,
	cwd => Path::Tiny->cwd,
};

init_vars($ref_var);
print $ref_var->{save_file}, "\n";

sub init_vars {
	my $rvars = shift;
	# ...
	$rvars->{save_file} = path( $rvars->{cwd}, "games",
		localtime->strftime("%d-%m-%Y-%H-%M-%S.txt") )->touchpath;
	# ...
}

##</code><code>##

use Path::Tiny;
use Time::Piece;
use Util::H2O;

my $ref_var = h2o {
	abs => path(__FILE__)->absolute,
	cwd => Path::Tiny->cwd,
}, qw/ save_file ... /;

init_vars($ref_var);
print $ref_var->save_file, "\n";

sub init_vars {
	my $rvars = shift;
	# ...
	$rvars->save_file( path( $rvars->cwd, "games",
		localtime->strftime("%d-%m-%Y-%H-%M-%S.txt") )->touchpath );
	# ...
}