sub makeMethod { 
  my $this = shift;
  $this->{_coderef} = eval $this->{_codestring} 
}
sub callMethod {
  my $this = shift;
  $this->{_coderef}->(@_)
}

##</code><code>##

$this->makeMethod( "somenewname", "some code" );
$this->somenewname();