>List!s are actually stored differently from blocks, paths and hashes, >so any operation on them requires special code that has not been >implemented for all action types. > - jim It makes sense, of course. If you need random access by position number then don't use a list. That is almost by definition. Use a regular block instead. Lists are I am guessing very efficient for certain algorithms requiring rapid insertion/deleetion and sequential access only. Since blocks are pretty fast, you would only need lists for getting the extra performance boost in some critical code with certain algorithms. Maybe the list also uses slightly less storage overhead per element? I doubt that the "special code" he refers to would be hard to write, it's just that it would be slow as hell, you would for instance get the 352nd element by starting at the head of the list and skipping down 352 times. Real Fast, eh? That's why you don't even want to do that. But think about implementing a fast stack, where you insert or push an object at the head of the list and pull or pop it also from the head. This is one job that a list can do really efficiently. I am sure others can think of more. I don't know if we have fast access to the tail of the list also. Normally one would assume that reaching the tail would be slow unless a pointer is kept to it specially. Basically, if you can't imagine why you would need a list, you probably don't need one.
