#! /bin/perl

use Data::Dumper;

my $hash = {
        'wheels' => {
                'four' => {
                        'car' => {
                                'plain' => {
                                        'sporty' => 'honda',
                                        'retro' => 'volkswagon',
                                        },
                                'fancy' => {
                                        'red' => 'ferrari',
                                        'silver' => 'maserati',
                                        },
                                },
                        'truck' => {
                                'light' => {
                                        'chevy' => 'pickup',
                                        },
                                'utility' => {
                                        'us' => 'mail',
                                        'city' => 'trash',
                                        'muni' => 'power',
                                        'corp' => {
                                                'dom'   => 'dominion power',
                                                'vap'   => 'virginia power',
                                                },
                                        },
                                },
                        },
                'one' => 'Unicycle',
                'two' => {
                        'pedals' => 'bicycle',
                        'motorized' => 'motorcycle',
                        },
                'three' => 'tricycle',
                };


##---------------------------
## DEEP REFERENCE
##---------------------------

fetch2($hash, 'wheels');
fetch2($hash, 'wheels', 'four', 'truck', 'utility', 'blah');
fetch2($hash, 'wheels', 'four', 'truck', 'utility', 'corp', 'dom');

## Using your suggested technique
sub fetch2 {
        my ($hash, @keys) = @_;
        print "==> Fetching [" . join(', ', @keys) . ']' . "\n";
        print Dumper $hash->{shift @keys}{shift @keys};
        }

##</code><code>##

==> Fetching [wheels]
$VAR1 = undef;
==> Fetching [wheels, four, truck, utility, blah]
$VAR1 = {
          'car' => {
                     'plain' => {
                                  'sporty' => 'honda',
                                  'retro' => 'volkswagon'
                                },
                     'fancy' => {
                                  'silver' => 'maserati',
                                  'red' => 'ferrari'
                                }
                   },
          'truck' => {
                       'light' => {
                                    'chevy' => 'pickup'
                                  },
                       'utility' => {
                                      'city' => 'trash',
                                      'muni' => 'power',
                                      'us' => 'mail',
                                      'corp' => {
                                                  'dom' => 'dominion power',
                                                  'vap' => 'virginia power'
                                                }
                                    }
                     }
        };
==> Fetching [wheels, four, truck, utility, corp, dom]
$VAR1 = {
          'car' => {
                     'plain' => {
                                  'sporty' => 'honda',
                                  'retro' => 'volkswagon'
                                },
                     'fancy' => {
                                  'silver' => 'maserati',
                                  'red' => 'ferrari'
                                }
                   },
          'truck' => {
                       'light' => {
                                    'chevy' => 'pickup'
                                  },
                       'utility' => {
                                      'city' => 'trash',
                                      'muni' => 'power',
                                      'us' => 'mail',
                                      'corp' => {
                                                  'dom' => 'dominion power',
                                                  'vap' => 'virginia power'
                                                }
                                    }
                     }
        };

##</code><code>##

==> Fetching [wheels]
$VAR1 = {
          'three' => 'tricycle',
          'one' => 'Unicycle',
          'two' => {
                     'pedals' => 'bicycle',
                     'motorized' => 'motorcycle'
                   },
          'four' => {
                      'car' => {
                                 'plain' => {
                                              'sporty' => 'honda',
                                              'retro' => 'volkswagon'
                                            },
                                 'fancy' => {
                                              'silver' => 'maserati',
                                              'red' => 'ferrari'
                                            }
                               },
                      'truck' => {
                                   'light' => {
                                                'chevy' => 'pickup'
                                              },
                                   'utility' => {
                                                  'city' => 'trash',
                                                  'muni' => 'power',
                                                  'us' => 'mail',
                                                  'corp' => {
                                                              'dom' => 'dominion power',
                                                              'vap' => 'virginia power'
                                                            }
                                                }
                                 }
                    }
        };

==> Fetching [wheels, four, truck, utility, blah]
  (nothing, because it doesn't exist)

==> Fetching [wheels, four, truck, utility, corp, dom]
$VAR1 = 'dominion power';