Sorry for the slow response - we've been wrapped up in a gigantic data migration at work...
On Tue, May 1, 2012 at 4:26 AM, Wolodja Wentland <babi...@gmail.com> wrote: > It certainly does, but I am none the wiser. I always had the > feeling/impression > that dynamic variables are something to be avoided, but I see them frequently > in Clojure code I read and therefore have the impression that they are "the > right thing to do"™ in a couple of instances. I think the problem is that "good" Clojure style is still evolving and a lot of the libraries were started a while ago before the "no dynamic variables" guideline really took hold. That's to be expected in a new and evolving language. I don't think clojure.java.jdbc is a very good example of idiomatic Clojure now but I'm sure it was considered good practice when it was originally built. I just looked at our codebase at work and the only things we have that are dynamic are: * global debug flags (set false, which can be rebound for specific call trees as needed) * global vars that defined external integration points (which can be rebound to test against other integration points: dev / test / prod, for example) I could probably reduce those further but five variables out of 4kloc production code doesn't seem bad (and a couple of those are primarily for mocking end points for testing - where I could use with-redefs, to be honest). > How would you, for example, implement the logging example I quoted above? What > about handling global configuration (config files, CLI options, ..) ? Logging is probably a good example because you don't want to have to pass flags thru your code (that's similar to what we do with our debug flags). For command line options, I would explicitly pass the map thru the code because I think that's cleaner in most cases. That said, for environmental configuration at World Singles, we have a delayed map for our environment settings and we require/refer that directly into code that needs it, e.g., (let [s @env/my-settings] ... (:some-value s) ...) Neither a dynamic variable nor something passed thru the code. -- Sean A Corfield -- (904) 302-SEAN An Architect's View -- http://corfield.org/ World Singles, LLC. -- http://worldsingles.com/ "Perfection is the enemy of the good." -- Gustave Flaubert, French realist novelist (1821-1880) -- 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
