On 9 October 2016 at 03:00, Phil Virgo <pwvi...@gmail.com> wrote: > WHY? > > The following prints 1/n 2/n 3/n fine in the repl > > (for [f [1 2 3]] (println f)) > > But does nothing in this lein project (the "Hello World???" does print) > > (ns slide.core > (:gen-class)) > > (defn -main > [& args] > ;; work around dangerous default behaviour in Clojure > (alter-var-root #'*read-eval* (constantly false)) > (for [f [1 2 3]] (println f)) > (println "Hello, World??")) >
The "for" macro is lazy. It only evaluates the items in the list when it's consumed. You want the "doseq" macro instead, which is used for side-effects. Incidentally, setting *read-eval* to false doesn't make clojure.core/read safe. You should always consider clojure.core/read to be unsafe for use with data from sources you don't control. Instead use something like clojure.edn/read, which is designed to be safe. - James -- 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.
