<pre class='rust rust-example-rendered'>
<span class='kw'>fn</span> <span class='ident'>main</span>() {
    <span class='kw'>let</span> <span class='ident'>a</span> <span class='op'>=</span> <span class='number'>5</span>;

    <span class='kw'>let</span> <span class='ident'>_y</span> <span class='op'>=</span> <span class='ident'>double</span>(<span class='ident'>a</span>);
    <span class='macro'>println</span><span class='macro'>!</span>(<span class='string'>&quot;{}&quot;</span>, <span class='ident'>a</sp