On Fri, Apr 27, 2012 at 22:21 -0700, Sean Corfield wrote: > On Fri, Apr 27, 2012 at 4:14 AM, Wolodja Wentland <babi...@gmail.com> wrote: > > Could you elaborate on that please? I see that dynamic variables are used > > quite > > often to give the user the ability to configure/change the behaviour of a > > library. That approach is often coupled with a macro that changes the > > bindings > > of dynamic variables. > > A better approach is to provide an API where the "changes" can be > passed in as function arguments. Dynamic variables smack of imperative > programming to me... > > When I asked Clojure/core to review c.j.jdbc in the context of a > potential future 1.0.0 release, the use of dynamic variables was one > of the issues that came up. The current variables will probably remain > for backward compatibility but a new API or an extension to the > current API will be added that provides a more functional style > without requiring dynamic variables - and the existing code rewritten > in terms of that new API. > > Hope that clarifies?
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 am definitely not trying to argue that they are, but I find it hard to develop a better style if all the libraries that I come across use dynamic variables. How would you, for example, implement the logging example I quoted above? What about handling global configuration (config files, CLI options, ..) ? Thanks a lot for your time and for helping me understanding this a bit better. -- Wolodja <babi...@gmail.com> 4096R/CAF14EFC 081C B7CD FF04 2BA9 94EA 36B2 8B7F 7D30 CAF1 4EFC
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