Combining more than one validation rule

[eluser]sheldonnbbaker[/eluser]
How does one combine validation rules? I'd like to write a simple username and password check callback function for a form validation function, but how can I access the posted username value when I'm checking the posted password value and vise-versa?

[eluser]pistolPete[/eluser]
[quote author="sheldonnbbaker" date="1235801684"]... how can I access the posted username value when I'm checking the posted password value and vise-versa?[/quote]

Code:

$password = $this->input->post('password');
$username = $this->input->post('username');

[eluser]sheldonnbbaker[/eluser]
Ah - easy enough... thanks again