Internals of Memoize (One slide only!)

	sub memoize {
	  my ($f_name) = @_;
	  my $f_ref = get_reference($f_name);
	  my %cache;
	  my $new_f = sub {
	    my $key = join ' ', @_;
	    return $cache{$key} if exists $cache{$key};
	    $cache{$key} = $f_ref->(@_);
	  };
          # Now do some magic to replace function $f with $new_f      
	}