On Thu, 18 Dec 2008 18:06:40 -0500 Chouser <chou...@gmail.com> wrote:
> > On Thu, Dec 18, 2008 at 4:47 PM, r <nbs.pub...@gmail.com> wrote: > > > > Is is possible to use some kind of backend storage for Clojure's > > data structures? I mean something like Perl's "tie" function that > > makes data structures persistent (in sense of storage, not > > immutability). > > > > Such storage should be inherently immutable the way Clojure's data > > are (so a simple wrapper on sql is probably not good enough) and > > provide means of querying database and indexing (ideally > > multidimensional). > > I would looove this. > This occurred to me the other day as well; the name "Mnejia" which popped into my head says a lot about the sort of thing I had in mind :) > > I wonder if this could be at library level or would rather have to > > be hard-coded into Clojure itself. Did anyone try to do it? > > I've pondered a couple approaches, though only enough to find > problems. > > One approach would work act like a Clojure collection, with structural > sharing on-disk. This would be great because it would have > multi-versioning and transaction features built right in. It would > also have the potential to cache some data in memory while managing > reads and writes to disk. > This is an interesting observation. Something in the vein of OTP's Mnesia for Clojure would be *very* cool indeed, and I have been thinking a lot about ways to implement distribution mechanisms for Clojure on top of which such a thing could be built. I imagine however that even sans distribution it would be quite powerful and useful, and a fun project. [ Mostly off-topic musings follow :) ] The big problem with mimicking Mnesia for distribution is that a lot of Erlang distribution idioms (used heavily in Mnesia AFAIK) rely on BEAM's ability to marshall funs across the network (and indeed I think Mnesia can even use that to serialize them on disk tables). If serialization of a fun is possible in Clojure, doing it is way over my head :) Obviously if you can serialize the sexp before the compiler gets ahold of it, this is easy, but usually you don't get that lucky. If one were able to marshall a Clojure fun, I had envisioned constructing a sort of "distributed send", probably built atop one of the many good message-queueing protocols already extant, that can be used to cause that fun to be run on a remote Agent, giving you a more Clojure-flavored distribution mechanism. Not RPC, but not exactly Actor model either. Hmmmm... :) -Kyle --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
