Convert text between newlines into html <p> tags.

newline-to-paragraph.php

<?php

public function nl2p($string) {
  $paragraphs = '';

  //split copy into pragraphs
  foreach (explode("\n", $string) as $line) {

    //trim line and if it isn't empty, add to output
    if ($line = trim($line)) {
      $paragraphs .= '<p>' . $line . '</p>';
   }

  }

  return $paragraphs;

}