Yes, I have a problem with CodeIgniter built-in Form Validation Library, the lack of direct Regular Expression test/rule is a huge turn off for me especially when I need to use Regular Expression to as a rule to verify user input.
There are alternative with the use of “callback” to by creating an additional method inside your Controller. The solution is good if you have a complex filtering but why bother when all you need to do is a simple RegExp verification. Based on my Twitter status:
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