nicolas.frisby:
I've got a first draft with the newtype and just an instance for list.
If you'd prefer fewer questions, please let me know ;)
0) I've cabalised it ("lazy-binary"), but I don't have anywhere to host it. Would it be appropriate to host on [1]darcs.haskell.org or HackageDB (yet?). Suggestions?
You can host it on code.haskell.org, ask for an account here: http://community.haskell.org/admin/account_request.html and a project: http://community.haskell.org/admin/
1) The fact that serialisation is fully strict for 32760 bytes but not for 32761 makes the direct application of strictCheck intractable. Do you have any ideas how to circumvent that?
((unLazy . decode . encode . Lazy) `asTypeOf` id) (take 32760 (repeat ()) ++ undefined) => undefined
((unLazy . decode . encode . Lazy) `asTypeOf` id) (take 32761 (repeat ()) ++ undefined) => lots of ()s and then undefined
What's happening here?
2) Also, any suggestions for other datatypes to provide default instances for? Tree type structures immediately raise the question of which traversal should be the default. I'm learning towards providing none since the goal of constant space usage actually depends on the serialisation order matching how the deserialised tree will be traversed.
Lazy Arrays?
3) I don't think it is applicable in anyway whatsoever to strict types like Int, Data.Set, and Data.Sequence? Counter-arguments?
Well, atomic types like Int, I don't think it makes sense, but Sets and Sequence are lazy, aren't they?
4) Perhaps the tight correspondence between serialisation and traversal necessary for constant space usage does indeed mean that the instance for the lazy list is the only appropriate one to provide. Perhaps the Chunks data type and a function splitN :: Int -> [a] -> Chunks [a] would also be helpful.
Yes, it is probably the only lazy instance anyone cares about, anyway.
-- Don