Id doesn´t have to create a copy of the original object ( I infer this from referential transparency) so the new list must store the same original reference. Any pure structure would conserve references after id. filter as far as I know. Am I wrong?
2010/4/8 Dan Piponi <dpip...@gmail.com> > I have a situation where I have a bunch of lists and I'll frequently > be making new lists from the old ones by applying map and filter. The > map will be applying a function that's effectively the identity on > most elements of the list, and filter will be using a function that > usually gives True. This means that there is potential for a large > amount of sharing between these lists that could be exploited, > something that ordinary lists would do badly. Does anyone have a > recommendation for a pure functional data structure for this case? > > (It reminds me a bit of my own antidiagonal type, but that's not well > adapted to the highly dynamic situation I'm describing.) > -- > Dan > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe >
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