PoHeader::tokenizeFormula

private PoHeader::tokenizeFormula($formula)

private function tokenizeFormula($formula) {
  $formula = str_replace(" ", "", $formula);
  $tokens = array();
  for ($i = 0; $i < strlen($formula); $i++) {
    if (is_numeric($formula[$i])) {
      $num = $formula[$i];
      $j = $i + 1;
      while ($j < strlen($formula) && is_numeric($formula[$j])) {
        $num .= $formula[$j];
        $j++;
      }
      $i = $j - 1;
      $tokens[] = $num;
    }
    elseif ($pos = strpos(" =<>!&|", $formula[$i])) {
      $next = $formula[$i + 1];
      switch ($pos) {
        case 1:
        case 2:
        case 3:
        case 4:
          if ($next == '=') {
            $tokens[] = $formula[$i] . '=';
            $i++;
          }
          else {
            $tokens[] = $formula[$i];
          }
          break;
        case 5:
          if ($next == '&') {
            $tokens[] = '&&';
            $i++;
          }
          else {
            $tokens[] = $formula[$i];
          }
          break;
        case 6:
          if ($next == '|') {
            $tokens[] = '||';
            $i++;
          }
          else {
            $tokens[] = $formula[$i];
          }
          break;
      }
    }
    else {
      $tokens[] = $formula[$i];
    }
  }
  return $tokens;
}