  function extract_plural_forms_header_from_po_header($header) {
    if (preg_match("/(^|\n)plural-forms: ([^\n]*)\n/i", $header, $regs))
      $expr = $regs[2];
    else
      $expr = "nplurals=2; plural=n == 1 ? 0 : 1;";
    return $expr;
  }
The software constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.