sub meta::define_form {
  my ($namespace, $delegate) = @_;
  $datatypes{$namespace} = $delegate;
  *{"meta::${namespace}::implementation"} = $delegate;
  *{"meta::$namespace"} = sub {
    my ($name, $value) = @_;
    chomp $value;
    $data{"${namespace}::$name"} = $value;
    $delegate->($name, $value);
  };
}