>/</code> operation in LPeg.)
It matches either <code>patt1</code> or <code>patt2</code>,
with no backtracking once one of them succeeds.
The identity element for this operation is the pattern
<code>lpeg.P(false)</code>,
which always fails.
</p>

<p>
If both <code>patt1</code> and <code>patt2</code> are
character sets,
this operation is equivalent to set union.
</p>
<pre class="example">
lower = lpeg.R("az")
upper = lpeg.R("AZ")
letter = lower + upper
</pre>


<h3><a name="op-sub"></a><code>patt1 - patt2</c