Laravel 3 – Using wpautop as a library

I decided to use the autop function from wordpress core to automatically transform line breaks from textareas into <p>s and <br>s, and use it in my libraries folder

(By the way Laravel doesn’t have any native way of doing this, right? I’d feel really stupid if it did)

So in myproject/application/libraries/formatting.php I have the following:

class Formatting {

    public function autop($pee, $br = true) {
       [wpautop's code here]
    }
}

And call it as

Formatting::autop($text);

so it returns this error

preg_replace_callback(): Requires argument 2, '_autop_newline_preservation_helper', to be a valid callback

It has to do with the following block

if ( $br ) {
    $pee = preg_replace_callback('/<(script|style).*?</\1>/s', '_autop_newline_preservation_helper', $pee);
    $pee = preg_replace('|(?<!<br />)s*n|', "<br />n", $pee); // optionally make line breaks
    $pee = str_replace('<WPPreserveNewline />', "n", $pee);
}

requiring this function to be there for him

function _autop_newline_preservation_helper( $matches ) {
     return str_replace("n", "<WPPreserveNewline />", $matches[0]);
}

This function is apparently responsible for turning single line breaks into <br> tags, If I remove the if block the code works but only with double line breaks, and I’d like to keep my <br>s

If I simply add this function’s code in the same file as the autop function it returns the same error, I dont know the proper way to include the _autop_newline_preservation_helper function, what should I do?