narfbg/CodeIgniter — comment on commit 901573ce19e905ce28a3f3345c33dedf9c703cd4
File: system/libraries/Form_validation.php line 604
By brodkin:

@narfbg I think you missed it... The guide says that the native PHP functions permit one parameter where they actually accept two. The second parameter can be passed using brackets in the rule definition as with other functions.