Generic tries (long)
isaacdupree at charter.net
Wed Jun 18 19:15:45 EDT 2008
Jamie Brandon wrote:
> Ive put up the haddock api at http://code.haskell.org/gmap/api/GMap.html
> The interface is now split into GMap which make no guarantees on
> ordering and OrderedGMap which provides a compareKey function as well
> as ordered folds etc.
>> Because all maps ought to be traversable.
> Thats a good point. Traversable requires Foldable. Do people expect
> Foldable to imply some ordering? I can put it into OrderedGMap at
Foldable does, trivially, imply ordering: "fold" can distinguish the
order. So you might have to be careful about breaking referential
transparency (at least if you want "==" GMaps to always be extensionally
equivalent). But obviously a container without some concept of ordering
will probably not be in any particularly *meaningful* order! It should
still be Foldable if there's no reason not to (which is useful at least
for commutative+associative ops like "+"). All IMHO.
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