l">&gt;</span></code>,
        we can directly use the expressions above to do both, parse input to fill
        the attribute:
      </p>
<pre class="programlisting"><span class="comment">// the following parses "1.0 2.0" into a pair of double</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">input</span><span class="special">(</span><span class="string">"1.0 2.0"</span><span class="special">);</span>
<span class="identi