+ *
+ * INSTANCE_TYPEABLEn(tc,tcname,"tc") defines
+ *
+ * instance Typeable/n/ tc
+ * instance Typeable a => Typeable/n-1/ (tc a)
+ * instance (Typeable a, Typeable b) => Typeable/n-2/ (tc a b)
+ * ...
+ * instance (Typeable a1, ..., Typeable an) => Typeable (tc a1 ... an)