#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
use Benchmark 'timethese';


timethese(
    100000, {
    'manual' => sub {
        my @arr = qw(aa bb cc dd ee ff);
        my %hash;
        my $ref = \%hash;
        while (defined (my $element = shift @arr)) {
            $ref = ($ref->{$element} = @arr ? {} : 0);
        }
        \%hash;
    },
    'eval_string' => sub {
        my $hoh;
        my @array = qw(aa bb cc dd ee ff);
        my %hash;
        my $eval_string = '$hoh->{' . (join '}{', @array) . '} = 0'; 
        eval "$eval_string";
        $hoh
    },
  }
);