use strict;
use warnings;

my $structure = {
    stuff => { 


        hierarchy => { 
            album => { 
                bar => 'the right one',
               },
        },  
    },
};

my $path = [ 'stuff', 'hierarchy', 'album' , 'bar' ];

print get_structure_value($structure,$path) , "\n";
$structure = return_new_structure($structure,$path,'new value');
print get_structure_value($structure,$path) , "\n";

sub make_eval {
    my ($path) = shift;
    my $string = "\$hashref->";
    $string .= "{$_}" for @$path;
    return $string;
}

sub get_structure_value {
    my ($hashref,$path) = @_;
    my $string = &make_eval($path);
    return eval($string);
}

sub return_new_structure {
    my ($hashref,$path,$set) = @_;
    my $string = &make_eval($path); 
    eval("$string = '$set'");
    return $hashref;
}