[nirvana:~] sporty% !vi
vi t.pl

sub x(&)
{
        my $a = shift;
        my @b = (1,2);
        map &{$a}, @b;
}

x { print $_ };
[download]

Is this what you were looking for? The prototype forces the block to be a code block. This works too...

sub x
{
        my $a = shift;
        my @b = (1,2);
        map &{$a}, @b;
}

x sub { print $_ };
[download]