# arg_1 to arg_n specify size in dimension k,
# last arg is a reference to a sub
# - expecting n arguments x1 ... xn
# - returning the desired value at $na->[x1]...[xn]
sub narray {
    my $size = shift;
    my $val = pop;
    my $na;
    for my $i (0 .. $size - 1) {
        $na->[$i] = @_ ? narray(@_, sub {&$val($i, @_)}) : &$val($i);
    }
    $na;
}

##</code><code>##

$ar = narray(3, sub {$_[0]});
# [0, 1, 2]

$mr = narray(3, 3, sub {$_[0] == $_[1] || 0});
# [[1, 0, 0], [0, 1, 0], [0, 0, 1]]

##</code><code>##

sub narray (&@);

$ar = narray {$_[0]} 3;

##</code><code>##

sub narray (&@);
sub narray (&@) {
    my $val = shift;
    my $size = shift;

    [map {my $i = $_; @_ ? narray {&$val($i, @_)} @_ : &$val($i)} (0 .. $size - 1)];
}

my $na = narray {"<@_>"} 3, 2
# [['<0 0>', '<0 1>'], ['<1 0>', '<1 1>'], ['<2 0>', '<2 1>']]