On Thu, Jan 8, 2009 at 1:28 AM, minh thu <not...@gmail.com> wrote: > Hi, > > I'd like to process some kind of graph data structure, > say something like > > data DS = A [DS] | B DS DS | C. > > but I want to be able to discover any sharing. > Thus, in > > b = B a a where a = A [C], > > if I want to malloc a similar data structure, > I have to handle to the node representing B > two times the same pointer (the one returned > after allocating A [C]). > > To discover sharing, I thought it would be > necessary to give unique name to node and > then compare them while traversing the graph. > I could give the name by hand but it would be > cumbersome. But at least it would not require > any monad for the bookkeeping of ungiven > names. Is it possible to give those names > automatically but outside any monad ?
If your graphs are acyclic, then you can label each node with a hash and use that for comparison. This usually works very well in practice. Luke
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