[XSL-LIST Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Cheaper to prepend or append an item to a sequence
How is that? If I have X=[1,2,3] ; Y=X ; Z=Y++[4]Even with a forward-chained list, you can implement append without copying if you choose, at least for the first append operation to a given list (which 9 times out of 10 will be the only append operation). When one list A is a sublist of another list B, A does not need separate storage - it can be implemented by means of pointers to the first and last items from B that are to be included in A. Therefore if A is not already a sublist of another list, you can create B by making a longer list and making A a sublist of the new list. Saxon does this using arrays rather than linked lists, but the same principle would work either way. Michael Kay Saxonica
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