http://dev.clojure.org/jira This file is an XML representation of an issue en-us 4.4 649 25-07-2011 http://dev.clojure.org/jira/browse/CLJS-210 ClojureScript <p>See discussion of Vars in CLJS here: <a href="http://dev.clojure.org/display/design/Dynamic+Binding">http://dev.clojure.org/display/design/Dynamic+Binding</a><br/> My goal is to eventually implement dynamic scope capture, via bound-fn and friends. The attached patch is a step in that direction.</p> <p>This patch adds support for parsing the (var foo) form. The #' reader macro is provided by JVM Clojure.</p> <p>#'foo emits code to construct a Var object. In this patch, each invocation of 'var will create a unique Var object. This means they are '= by fully qualified symbol, but not 'identical?. Simple memoization would fix that, but I'm not going to bother until I get to Dynamic Var objects.</p> <p>The main advantage of this level of Var support is for the interactive development convenience of being able to defer dereferencing top-levels. For example, (def fog (comp f #'g)) will pick up redefinitions of 'g, but not of 'f.</p> CLJS-210

Implement Var form, var-get, and var? in CLJS

Enhancement Minor Open Unresolved Unassigned Brandon Bloom patch, Fri, 27 Apr 2012 22:51:28 -0500 Sun, 28 Oct 2012 21:03:58 -0500 0 2 <p>I found two issues with this patch:</p> <p>1) I never used the IVar that I declared :-P</p> <p>2) (apply #'+ (range 100)) throws "Invalid arity: 101" &#8211; this is related to <a href="http://dev.clojure.org/jira/browse/CLJS-211">http://dev.clojure.org/jira/browse/CLJS-211</a></p> <p>I'll look into fixing both. However, we should discuss supporting variable arity protocol methods...</p> <p>any support for reified vars is a low priority for the foreseeable future.</p> <p>Reified vars (and binding frames!) are a requirement for a CPS transform to be correct with respect to dynamic bindings.</p> <p>+1 towards bound-fn and friends. I had an explanation written here but now I see "async Javascript (ie. nearly all Javascript) makes the binding macro effectively useless without bound-fn". Indeed.</p> <p>bound-fn could also be implemented by setting / resetting bound vars before / after the wrapped fn, similar to binding. We would just need to add tracking of the currently rebound dynamic vars.<br/> That should also be CPS - friendly, no?</p> <p>I've considered that and would love to see it happen.</p> <p>But what about:</p> <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent"> <pre class="code-java">(def ^:dynamic *foo* 3) (set! *foo* 4) (def f (bound-fn [] *foo*)) (set! *foo* 5) (f)</pre> </div></div> Global Rank Patch Code and Test