my @foo_subs = ( 'sub { return ( 4, 5, 6 ) }',
                 'sub { my @x = ( 4, 5, 6 ); return @x; }',
                 'sub { wantarray ? ( 7 ) : 8 }',
               );
foreach my $foo_str ( @foo_subs ) {
    my $foo = eval $foo_str;

    my ($x) = $foo->();
    my  $y  = $foo->();

    print "foo = $foo_str\n";
    print "(\$x) = $x\n";
    print " \$y  = $y\n";
}
__END__
foo = sub { return ( 4, 5, 6 ) }
($x) = 4
 $y  = 6
foo = sub { my @x = ( 4, 5, 6 ); return @x; }
($x) = 4
 $y  = 3
foo = sub { wantarray ? ( 7 ) : 8 }
($x) = 7
 $y  = 8