nctional languages. It takes two or three parameters: a condition, an
expression to evaluate to if the condition is Boolean true (ie: not <code class="mendoza-code">nil</code>
or <code class="mendoza-code">false</code>), and an optional condition to evaluate to when the condition is
<code class="mendoza-code">nil</code> or <code class="mendoza-code">false</code>. If the optional parameter is omitted, the <code class="mendoza-code">if</code>
form evaluates to <code class="mendoza-code">nil</code>.
</p>
<pre 