 to
    <code>lex:add_fold_point()</code>. Returning <code>1</code> indicates the token is a beginning fold
    point and returning <code>-1</code> indicates the token is an ending fold point.
    Returning <code>0</code> indicates the token is not a fold point. For example:</p>

    <pre><code>
    local function fold_strange_token(text, pos, line, s, symbol)
      if ... then
        return 1 -- beginning fold point
      elseif ... then
        return -1 -- ending fold point
      end
      return 0
    