Saving form data when POST submission is not validated

[mapletard]

I need to validate a form in php and display some error messages in the view if there are validation errors. The problem is that once the form is submitted, sending the user back to the page will clear all the of the completed form fields. Is there a simple way to not lose the unvalidated form data? The only solution I can come up with is reverse engineering the \[code\]$_POST\[/code\] variable, but I'd like a more elegant way to do it.Thanks!