Form validation rule question

[eluser]mrh[/eluser]
Hello all...

After searching the forums I figured out from a prior post that for set_value to work you have to define a rule for it in validation rules. So I've done that. For each field I've defined a rule like:

Code:

array (
  'field' => 'directorEmail',
  'label' => '',
  'rules' => 'trim'
  );

My questions are:

a) Do rules in the $config array run in order so that these "trim" rules would run BEFORE any custom rules I create at the end of the array?

b) Do these "trim" rules replace the post value? So I don't have to trim the data later? IE running these rules means I don't need to do trimming in my custom validation functions like this:

Code:

$_POST['directorEmail'] = trim( $_POST['directorEmail'];