on</span>.<span class='ident'>is_some</span>() {
    <span class='kw'>let</span> <span class='ident'>x</span> <span class='op'>=</span> <span class='ident'>option</span>.<span class='ident'>unwrap</span>();
    <span class='ident'>foo</span>(<span class='ident'>x</span>);
}</pre>

<!-- Neither of these options is particularly appealing. We can use `if let` to -->

<!-- do the same thing in a nicer way: -->

<p>上述のコードのどちらもまだ理想的ではありません。 <code>if let</code> を�