Custom form validation rule

You do need to avoid using the pipe (|), because set_rules() will explode the rules on that character (so, in your rules, it would attempt to call a function named "{$current_title}]", and the is_unique rule definition is messed up because it's missing the closing bracket).

You should be able to pass anything you'd like in $field (except the pipe). CI's is_unique() function uses sscanf, but you don't have to.

I would recommend using a different function name, though, and leaving is_unique() alone. Bonfire has a unique() function which does something similar to what you seem to be describing.

Bonfire

Practical CodeIgniter 3
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