>line</code>: The text of the line currently being processed.</li>
    <li><code>s</code>: The position of <em>start_symbol</em> in <em>line</em>.</li>
    <li><code>symbol</code>: <em>start_symbol</em> itself.</li>
    </ul>


    <p>Parameters:</p>

    <ul>
    <li><code>lexer</code>: The lexer to add a fold point to.</li>
    <li><code>token_name</code>: The token name of text that indicates a fold point.</li>
    <li><code>start_symbol</code>: The text that indicates the beginning of a fold point.</li>