'Major task to perform?' => ['task_1','task_2','task_2'],

##</code><code>##

    'Major task to perform?' =>
       {
         answers => [ 'Add',   'Delete', 'Rename' ],
         keys    => [ 'task_1','task_2', 'task_2' ],
       },

##</code><code>##

my $current_key = 'Major task to perform?';
while ( my $choice = prompt( $current_key, ...)) {
    # set INDEX to offset of $choice in $structure{ $current_key }{answers}
    # if $structure{$current_key}{keys}[INDEX] is empty
    #        break out of loop; you;'re in a terminal state
    # else $current_key = $structure{$current_key}{keys}[INDEX]
}
<p>A lot of the code is left as an exercise to the reader. Good luck with your class.