On Friday, November 14, 2014 7:22:39 PM UTC-8, Colin Fleming wrote: > Hi all, > > There's a discussion going on right now on clojure-dev > (https://groups.google.com/d/topic/clojure-dev/6pnIeXFRwnI/discussion) about > the Feature Expressions functionality currently slated for Clojure 1.7. This > was one of the most requested features in the recent state of clj/cljs > survey, particularly by cljs users. However there seems to be a lot of > confusion about exactly what the needs are here. I think everyone would be > very interested in feedback, either here or on the clojure-dev thread if you > have access, on why this is so important to cljs users. Specifically: > Is there something specific in the current proposal that is especially > attractive to you, or is Feature Expressions more a proxy for "it should be > easier to write cross-platform code"?Is there a strong argument for having > this in the language, instead of in a tool like CLJX? Is this a fundamental > failing of CLJX, or is the tooling perhaps just more awkward to use than it > could be? > Could these needs be totally or mostly met by better cross platform > libraries, like string and date handling?Would more features be useful than > simply "this is CLJS code", i.e. would this be helpful for Node support? Is > there no other way to get that support, i.e. through better libraries or > macros? > I don't know the answers to any of these questions or have strong opinions > about them since I don't use CLJS or CLJX, but I do write tooling that has to > support them so I'd really like to understand this better. > > If any of you are interested in this and will be at the conj, there'll be an > unsession about Feature Expressions there - please come and tell us what you > think! > Cheers, > Colin
I'm primarily a ClojureScript dev but I sometimes work with Clojure on the JVM as well. Here's my perspective. 1. I have no strong feelings about feature expressions in particular; I'm just excited to see the core team endorsing anything that will make cross-platform development simpler out of the box. 2. I have no major problems with CLJX (I suppose it's a bit of a hack, but it suffices for my purposes) except that of adoption. If I want to make any of the Clojure core repos CLJS-compatible, I can't use CLJX to write shared platform-agnostic code – the core team doesn't allow it. If a particular JVM Clojure library's maintainer doesn't like CLJX for whatever reason, I can't use that library in my CLJS project without forking it and maintaining the fork. At the moment, Clojure and CLJS code are incompatible by default, which feels like the opposite of how things "should be". 3. Better cross-platform libraries might get us halfway there but they won't completely obviate the need for CLJX, feature expressions, or something similar. When trying to write cross-platform exception handling code, for instance, I still regularly find myself needing to replace instances of "Exception" with "js/Error"; as long as these sorts of situations are still coming up I'll always want to have something like CLJX or feature expressions in my toolbox. 4. I can't really speak to this point too much, as I've never really run into any problems trying to work with e.g. Node vs browser JS. In the long term it might make sense to divide the "Clojure platform" into a set of specific features (e.g. macros, reified namespaces, clojure.string, etc) and allow users to test whether each of these features is "present" on any given implementation, but whether there exists an actual use-case for this is beyond me and it seems totally out of scope for the current discussion anyway. To get on my soapbox for a bit, I think the gap between Clojure and CLJS is gradually widening because the language as currently implemented makes it difficult to write and maintain cross-platform code. CLJX's feature set is all I really need, but right now every member of the community has to specifically "opt in" to writing cross-platform code by manually setting up CLJX for every project. Couple that with the fact that I specifically can't use CLJX when I'm contributing to the core libraries, and we wind up with a lot of duplicated effort on both sides of the Clojure/CLJS fence. The sooner we get feature expressions or something equivalent baked into core, the better. Only once the core team has blessed a particular solution will we see the current situation replaced by the "cross-platform by default" scenario I'd prefer. -- Note that posts from new members are moderated - please be patient with your first post. --- You received this message because you are subscribed to the Google Groups "ClojureScript" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/clojurescript.
