I'm not aware of any, but +1 for seeing persistence handled as part of the language. A big project and a long-term one, to be sure, but could it not be considered a goal?
In my student days, I was talking to a well-known Lisper (name suppressed for fear of Google indexing) about some data structures in MIT Scheme. When I asked about saving them to disk, he said in effect, "You're on your own----that's something that \should be handled, but never is". I think people are so used to this state of affairs they forget how ugly it really is. Programming languages are like Moses without Joshua: they lead your data in the wilderness, but when it comes to finding it a permanent home, you have to talk to someone else. And these "someone elses" (who seem to be as numberless as the sons of Abraham) each have their own habits and ways of talking. Persistence libraries always end up warping the entire codebase; I've never succeeded in keeping them at bay. Using data with Incanter is different from ClojureQL, which is different from just using contrib.sql, and all of it is different from dealing with just Clojure. (I've never even tried Clojure + Hibernate.) You might as well rewrite the program from scratch depending on what you use. Maybe other people have had better luck; but whatever luck they have, I'm sure it is a fight to keep programs abstracted from persistence. I'd like to be able to work with mere Clojure until my program is complete, and then work in a completely separate manner on how to read and write data. Or maybe there would be off-the-shelf solutions I could plug in for different needs: low latency, high read, high write, large stores, etc. On the Clojure side, you would simply call something like "persist namespace", which would save the state of your current or given namespace (unless you pass it the names of variables as well, in which case it only saves those). And to read data, you would simply require or use it into your namespace: you could choose what granularity to give first-class status: just tables, or columns as well, etc. And you could do this equally well for XML, JSON, relational data, or a graph store; your choice. And the only difference between these and ordinary variables would be----heaven forbid!----a disk access might happen when you deal with them! To have such a system work well, you would need to enrich the way you query Clojure datastructures. I have some ideas on that, but I'd like to make sure I'm not shouting in the dark first. I'd like to see a day when programmers need to worry about persistence about as much as they worry about garbage collection now. -- 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 Note that posts from new members are moderated - please be patient with your first post. 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
