my $f = sub { return 'a sub' };
print "\$f is ${\$f->()}\n";

__output__

$f is a sub

##</code><code>##

my $f = sub { return 'a sub' };
# list
print "\$f is ", $f->(), "\n";
# concat
print "\$f is ". $f->(). "\n";
# save return
my $ret = $f->();
print "\$f is $ret\n";