Filter input

Hi all, I repeat the mantra 'filter input, escape output' every day before writing any line of code. About "filter input" I use to develop my own filter but I don't like this solution as it's error prone (my regexp may be wrong, I don't like to re-invent the wheel that much, ...). I'd like to know if there is a library that could help me. I identified: - PEAR Validate: * seems nice * but no activity since ~1year and still "beta". - PEAR HTML_QuickForm: * validation is a part of its job. * not very usable if you only want to validate input (need to declare each element before, access to invalid element not easy). - PHP Filter: * Require php 5.2 * As it's embedded in the php core, if there is a security hole we need to wait for a new php version to fix the bug. Is there any other library I need to investigate ? What are you using for your own developments ? -- Manuel