Definition of NullValue for Cell Objects

[rdbyk]

is currently the empty matrix [], however anything can be assigned to cell element, cf. below

--> L=list();L(2)=2; // L(1) is now Undefined
--> C{1}=L(1)
 C  = 
  [  listundefined]

--> C{1}=null()
 C  = 
  [  listdelete]

--> C{1}=insert()
 C  = 
  [  listinsert]

Thus, it seems to be more consistent (wrt to lists) to use ListUndefined as "NullValue" for cell objects (which, of course, should be renamed Undefined). We hear you whispering "this would break compatibility with M ...". Well, ask yourself is S really compatible to M? Do you really expect S to become fully compatible to M one day? Why don't you use O?