I wouldn't consider this a bug or even an unfortunate behavior necessarily, but potentially surprising and worth mentioning. The comment reader macro #_ works just fine as long as nothing breaks the reader. The surprise happens when you don't consider that for namespaced keywords using ns aliases, the namespace resolution happens at reader-macro expansion time, prior to evaluation. As a logical consequence of this is that seemingly commented out code will fail at read-time if the ns alias or namespace doesn't exist.
Clojure repro: user=> (println #_(::fooo/bar)) RuntimeException Invalid token: ::fooo/bar clojure.lang.Util.runtimeException (Util.java:221) RuntimeException Unmatched delimiter: ) clojure.lang.Util.runtimeException (Util.java:221) user=> RuntimeException Unmatched delimiter: ) clojure.lang.Util.runtimeException (Util.java:221) ClojureScript repro: cljs.user=> (println #_(::fooo/bar)) cljs.user=> clojure.lang.ExceptionInfo: [line 1, col 23] Invalid keyword: ::fooo/bar. {:type :reader-exception, :ex-kind :reader-error, :file nil, :line 1, :col 23} at clojure.core$ex_info.invokeStatic(core.clj:4739) at clojure.core$ex_info.invoke(core.clj:4739) at clojure.tools.reader.impl.errors$throw_ex.invokeStatic(errors.clj:34) at clojure.tools.reader.impl.errors$throw_ex.doInvoke(errors.clj:24) ... -- 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 --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.