sub myaction : Chained('.') PathPart('myaction') POST {
    my ( $self, $c ) = @_;

    my $form = MyApp::Form->new;
    $form->process(params => $c->req->body_params);

    my $error_sub = sub {
        $c->response->status(400);
        $c->stash(
            results => {
                form => $form->render,
            },
        );
        $c->detach();
    };

    if ( $form->is_valid ) {
        try {
            $form->update_model;
        }
        catch($e) {
            $form->add_form_error($e);
            $error_sub->();
        };
    }
    else {
        $error_sub->();
    }
}


##</code><code>##

   my sub error {
        $c->response->status(400);
        $c->stash(
            results => {
                form => $form->render,
            },
        );
        $c->detach();
   }