use Data::Diver qw( DiveVal );

my @keys = map "level$_", 1 .. 3;

my $branch = {};
DiveVal($branch, map \$_, @keys) = 'leaf';
  -or-
my %branch;
DiveVal(\%branch, map \$_, @keys) = 'leaf';

##</code><code>##

sub DiveVal :lvalue {
   my $p = \shift;
   $p = \( $$p->{$_} ) for @_;
   $$p
}

my @keys = map "level$_", 1 .. 3;

my $branch;
DiveVal($branch, @keys) = 'leaf';
  -or-
my %branch;
DiveVal(\%branch, @keys) = 'leaf';

##</code><code>##

Pre-loop:          $p references $branch
After loop pass 0: $p references $branch->{level1}
After loop pass 1: $p references $branch->{level1}{level2}
After loop pass 2: $p references $branch->{level1}{level2}{level3}
Returned:          $branch->{level1}{level2}{level3}