Codeigniters form_validation is great, however I need a custom filter that is specifically
alpha space dash and apostrophe/single quote
but.. they don't have that specifically in there existing set, so I am wondering how could I go about creating my own rule/filter and adding it to form_validation.
Callbac ks are your friend
You'll just just a custom callback - and put a regex in there that does whatever rule you want.
Here is some documentation for CodeIgniter's form validation tool.
http://codeigniter.com/user_guide/libraries/form_validation.html#validationrules