or | - sequence operator , - subexpressions (...) - usual cardinality operators + * and ? - finite sequences { min, max } - infinite sequences { min, * } There is minimal checkings made especially no checking on strings values</p>
<div class="variablelist"><table border="0"><col align="left"/><tbody><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>the expressions context</td></tr><tr><td><span class="term"><i><tt>expr</tt></i>:</span></td><td>the 0 terminated string</td></tr><tr><td><span cl