converting a text into a hash datastructure

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi all, I have a string like this.

my $text = "a.b.c.d";
[download]

I would like to get this converted into

my $hash = {
 a => {
         b => {
                c => d 
              }
      }
};
[download]

Could any one please help me with some efficient way to achieve this..