define additional root classes, but this is tricky, and not really to be
recommended.
+
\subsection{The SodObject class} \label{sec:structures.root.sodobject}
\begin{figure}[tbp]
\xref{fig:structures.root.sodobject}.
\end{describe}
+
\subsection{The SodClass class} \label{sec:structures.root.sodclass}
\begin{describe}[SodClass]{cls}
while the corresponding lowercase letters indicate the class nicknames.
Throughout, we consider a class $C$ (therefore with nickname $c$).
+
\subsection{Generic instance structure}
\label{sec:structures.layout.instance}
Finally, the @|islots| structure simply contains one member for each slot
defined by $C$ in the order they appear in the class definition.
+
\subsection{Generic vtable structure} \label{sec:structures.layout.vtable}
As described above, each @|ichain| structure of an instance's storage has a
@<type>_n @<arg>_n, va_list sod__ap);
\end{prog}
+
\subsection{Additional definitions} \label{sec:structures.layout.additional}
In addition to the instance and vtable structures described above, the