[] =$>$ ${\it body}$ ${\it cont}$(${\it value}$,${\it contvalue}$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$Case of ${\it value}$; nil $\rightarrow$ ${\it body}$ ; ${\it hd}$.${\it tl}$, rec:$f$ $\rightarrow$ ${\it cont}$(${\it contvalue}$,${\it contvalue}$)