(VAR x y z)
(RULES
int(0,0) -> .(0,nil)
int(0,s(y)) -> .(0,int(s(0),s(y)))
int(s(x),0) -> nil
int(s(x),s(y)) -> int_list(int(x,y))
int_list(nil) -> nil
int_list(.(x,y)) -> .(s(x),int_list(y))
)
(COMMENT Example 4.27 (List of Integers) in \cite{SK90})