That's interesting... Hadn't thought of using delay. A user on Stackoverflow (kotarak) suggested using alter-var-root. This method will also support setting values for command line arguments.
On Oct 24, 3:33 pm, Stuart Sierra <the.stuart.sie...@gmail.com> wrote: > Here's one way: > > (def version (delay (... read the JAR ...)) > > (defn get-version [] (force version)) > > -S > > On Oct 22, 11:56 am, Ralph <grkunt...@gmail.com> wrote: > > > > > I have a Clojure program that I build as a JAR file using Maven. > > Embedded in the JAR Manifest is a build-version number, including the > > build timestamp. > > > I can easily read this at runtime from the JAR Manifest using the > > following code: > > > (defn set-version > > "Set the version variable to the build number." > > [] > > (def version > > (-> (str "jar:" (-> my.ns.name (.getProtectionDomain) > > (.getCodeSource) > > (.getLocation)) > > "!/META-INF/MANIFEST.MF") > > (URL.) > > (.openStream) > > (Manifest.) > > (.. getMainAttributes) > > (.getValue "Build-number")))) > > but I've been told that it is bad karma to use def inside defn. > > > What is the Clojure-idiomatic way to set a constant at runtime? I > > obviously do not have the build-version information to embed in my > > code as a def, but I would like it set once (and for all) from the > > main function when the program starts. It should then be available as > > a def to the rest of the running code. -- 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
