Hi Tony, that's because I wasn't sure whether or not it would be applicable here. As with monads, continuations, delimited continuations and quite a number of other high level concepts I only understand them in part even though I realize at the same time that understanding them fully would yield enormous benefits. I am aware of the power of these concepts, but have not gained the intuition yet. As for the zipper: In some of the examples I've seen, the zipper is implemented "on top" of an underlying data structure, but not the data structure itself. In my app I was actually going to pull a zipper over it, once I had the underlying structure right. Günther PS: please also see my reply to Tillman Tony Morris schrieb:
I note that you didn't address the suggestion of a zipper.
Günther Schmidt wrote:
Dan Weston schrieb:
Unless I'm missing something in your description, why not
data Container a = Single a | Many a a [a]
Hi Dan,
the above solution would still allow to construct, for instance,
Many 5 42 [] :: Container Int
The reason why I'm trying to find the design for a data structure in which this would not even be possible is to be able to avoid writing additional "bookkeeping" code into the functions that operate on the structure, ie. the lookups, inserts, delete etc.
Günther
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