\section{SUBSREF Overloaded Class Indexing}

\subsection{Usage}

This method is called for expressions of the form
\begin{verbatim}
  c = a(b), c = a{b}, c = a.b
\end{verbatim}
and overloading the \verb|subsref| method allows you
to define the meaning of these expressions for
objects of class \verb|a|.  These expressions are
mapped to a call of the form
\begin{verbatim}
  b = subsref(a,s)
\end{verbatim}
where \verb|s| is a structure array with two fields. The
first field is
\begin{itemize}
\item  \verb|type|  is a string containing either \verb|'()'| or
 \verb|'{}'| or \verb|'.'| depending on the form of the call.

\item  \verb|subs| is a cell array or string containing the
 the subscript information.

\end{itemize}
When multiple indexing experssions are combined together
such as \verb|b = a(5).foo{:}|, the \verb|s| array contains
the following entries
\begin{verbatim}
  s(1).type = '()'  s(1).subs = {5}
  s(2).type = '.'   s(2).subs = 'foo'
  s(3).type = '{}'  s(3).subs = ':'
\end{verbatim}
