ess
<code>nxleft</code> and <code>nxright</code>. Note, that in this example we
only store the locations of leaves directly. In a convenient implementation
of the AST, we would expect a recursive function, that computes the locations for each
intermediary node in the tree.
</p>

<a name="symbolstream-caching"></a>
<h4>5.3 Symbolstream caching</h4>

<p>CUP offers an additional layer between scanner and parser, in order to cache the
actual sequence of terminal symbols, provided by the scanner for potential la