We have the common use-case that we want to use double-colon keywords for well known namespaces, without actually requiring the namespaces.
(defmacro ns-alias "Set up a custom alias for use with namespace keywords." [ns as] `(do (create-ns '~ns) (alias '~as '~ns))) This proved useful to prevent cyclic requires while still being able to use the shorthand syntax for long and common namespaces. Cheers, Dieter On Wednesday, 30 January 2019 11:53:15 UTC+1, Thomas Heller wrote: > > To expand on what Alex already mentioned. There is no such thing as > double-colon keywords. Double-colon is a reader alias mechanism that let > the reader resolve them so you can type less. > > (ns foo.bar.xyz) > > ::hello > > this is resolved at read-time and identical to actually writing > > :foo.bar.xyz/hello > > :: without a slash will use the current namespace as the namespace for > the keyword. > > If you have a require for another namespace and use :: with a slash you > can use it to resolve your require alias. > > (ns some.thing > (:require [foo.bar.xyz :as x])) > > ::x/hello > > again becomes > > :foo.bar.xyz/hello > > in your actual program. Nothing :: will ever exist at runtime. > > So if you want you can always use the fully qualified keyword directly or > you can let the require resolve them based on your ns require's. That means > you'll get an error if there is no alias to resolve > > (ns user2) > > ::user1/foo > > This is invalid because user2 does not have an alias to user1, instead it > is an actual full namespace. > > :user1/foo > > would be fine in this case (and identical to ::foo in user1). Or > > (ns user2 > (:require [user1 :as u1])) > > ::u1/foo > > Hope that makes things clearer. > > Cheers, > Thomas > -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/clojure/cd2b56d9-8bab-45c6-8e7a-42636a6dcef6%40googlegroups.com.