.</span><span class=identifier>end</span><span class=special>(), </span><span class=identifier>is_odd</span><span class=special>(</span><span class=identifier>arg1</span><span class=special>))
</span></pre></code>
<p>
is_odd_ is the actual functor. It has been proxied in function&lt;is_odd_&gt; by is_odd (note no trailing underscore) which makes it a lazy function. is_odd_::operator() is the main function body. is_odd_::result is a type computer that answers the question &quot;What should be our return type