[vtk-developers] Containers and... String

[David Gobbi]

Hi Andy,

I think this is a very good idea.  Here are a few comments:

On Mon, 21 Jan 2002, Andy Cedilnik wrote:

> Hello!
>
> So, to continue the discussion about containers,
> I suggest the following simple hierarchy of containers:
>
> Abstract base class: vtkContainer
> 	- Defines things such as Number of elements, capacity,
> 	  interface for clean and is empty
>
> Two abstract subtrees: vtkAssociativeArray and vtkList
> 	- List defines operations such as:
> 		Insert, append, prepend, push, pop, lookup,
> 		find, remove, shift, rotate, etc
> 	- Associative array defines:
> 		Set, Remove, Find
>
> List contains:
> 	- vtkVector, which is a dynamic array implementation of
> 		List data structure

Instead of making a vtkVector class, just expand the vtkCollection
class (which is already used all over the place).  I would love,
for example, to be able to use the collection[] and *collection++.

> 	- vtkLinkedList, which is a linked list implementation

Unnecessary as far as I can see, it's probably best not to provide
a linked list.

> AssociativeArray contains:
> 	- vtkHashTable, which is a hash table implementation

An efficient hash table would be a very useful thing.

> 	- vtkTree, which is a (red-black) tree implementation

Again, possibly unnecessary.

> 	- vtkArrayTable, which is an array implementation

I'm not quite sure what this is.

> vtkContainer class is not subclass of vtkObject, so that we
> can use containers inside vtkObject class for things such
> as Observers.

I would much prefer that the containers are subclassed from
vtkObject, so that they can be reference counted etc.  Also,
wrapping classes that are not derived from vtkObject is a pain.
Finally, I would like it if all the 'items' in the containers
are vtkObjects.

> Comments?
>
> On the side note, I also think we need a vtkSring class.

Again, I would like to see this derived from vtkObject.  It should
specifically be a 'vtk string', not just a re-implementation of
the stl string (re-implementing stl strings would be a rather
pointless exercise IMHO).

 - David