I know that this has come up before on the group and but is this not essentially dependency injection where the dependency being injected is a name space that presumably follows a particular convention in terms of what functions it provides?
I remember people making it pretty clear that they didn't see the need for DI in Clojure so my question is, is this a useful approach? is there a better way? Cheers, James On Sep 7, 3:17 pm, Cliff Wells <cl...@twisty-industries.com> wrote: > Hi, > > I'm new to Clojure (and Lisp-type languages in general) and I've never > used Java... in short, I have a steep learning curve littered with rocks > and nails. I also don't know whether it's a good thing that I have > long experience with Python and C :-P > > In any case, as a first project, I'm trying to add PostgreSQL support to > Clogger (http://github.com/Ejhfast/Clogger/tree/master) and I've managed > to get it working. > > *But*, the number of changes involved suggest that I should put the > existing MySQL code and the new PostgreSQL code into a separate files > and pull in the correct one at runtime based on a configuration > variable. This is where I'm choking. > > I've created a global variable *db-adapter* in setup.clj and would like > change > > http://github.com/Ejhfast/Clogger/blob/dce291524ab76796c781f720020707... > > to selectively :use (or :import or whatever) mysql.clj or postgresql.clj > based upon the value of *db-adapter*. In turn, mysql.clj and > postgresql.clj will contain custom versions of the "db" and > "create-blog" code from database.clj (this leads to a second issue, but > I'll save that for later). > > What I've tried (no laughing!) is this bit of code: > > (ns site.database > (:use [compojure]) > (:use [clojure.contrib.sql]) > (:use [site.setup]) > > (if (= *db-adapter* "mysql") > > > (:use [site.adapters.mysql :as adapter])) > > > (if (= *db-adapter* "postgresql") > > > (:use [site.adapters.postgresql :as adapter]))) > > But this throws an error: > > java.lang.Exception: No such var: clojure.core/if (database.clj:1) > > In any case, this code smells funny, even if it were to work. It seems > I should be able to somehow build a string such as (str "site.adapters." > *db-adapter*) and use that instead (or something else equally concise). > > And of course, this isn't my only problem. But I'll keep it to one > issue at a time. > > Regards, > Cliff --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
