On Monday, August 3, 2015 at 10:21:09 PM UTC-5, Dmitri wrote: > > My understanding is that the problem is actually caused by the stateless > nature of the functions. >
You're talking about database interactions. By definition, those are not stateless. The trick is to isolate this statefulness as much as possible. Expanding it just compounds the problem. > Since the function accepts the connection as a parameter it's up to the > user of the function to ensure that it's passed the correct connection. > That depends on what you mean by "user of the function." If I'm working on the web server front-end, I shouldn't have any idea about the database connection. I should describe what I want to happen. If I have any concept that multiple databases are involved (I shouldn't, but abstractions leak), then, yes, I have to specify which one I mean. This isn't complicated. It's up to the person writing the database back-end code (also possibly me, if we're talking about a start-up, but then we aren't talking about the 200 KLOC scenario) to turn that description into the side-effects. > Every functional solution presented in this thread suffers from this same > fundamental problem that the function is not aware of the context it's > being run in. > That isn't a problem: it's a feature. It doesn't matter what language or programming paradigm you're using in this context. This cuts across problem domains and architectures. The actual database interaction code should be as brain-dead simple (not "easy") and bullet-proof as you can possibly make it. And it should be as isolated from the front-end code as you can get away with making it. That isn't a "right" answer. But it's a good rule of thumb. And you should have very hefty reservations (and very good reasons) about violating it. Respectfully, James -- 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 --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
