this.
\subsection{Case normalisation}
+ The transformations in this section ensure that case statements end up
+ in normal form.
+
\subsubsection{Scrutinee simplification}
This transform ensures that the scrutinee of a case expression is always
a simple variable reference.
This transformation ensures that all case expressions get a form
that is allowed by the intended normal form. This means they
will become one of: \refdef{intended normal form definition}
+
\startitemize
\item An extractor case with a single alternative that picks a field
from a datatype, \eg\ \lam{case x of (a, b) -> a}.