="example">
struct payload{
    enum {ICMP,ARPFOUR,IPFOURE} N_type;
    union {
        icmp icmp;
        arpfour arp;
        ipfour ipfour;
    };
}
</pre>

</td></tr>
</table></center>

</section>
<section id="sec-7-1-2" >

<h4>Semantic bijection</h4>
<ul class="org-ul">
<li>Sometimes, bijection is tricky
</li>
</ul>

<div class="org-src-container">

<pre  class="src src-c">padded_string={
  contents many uint8 | ![0]
  many (uint8=0)
}
</pre>
</div>


<ul class="org-ul">
<li>Semantic bijection
<ul clas