What is an elegant way to set up a leiningen project that requires different dependencies based on the build platform?

Question

In order to do some multi-platform GUI development, I have just switched from GTK + Clojure (because it looks like the Java bindings for GTK never got ported to Windows) to

Answer 1

Here's a quite elegant solution using Java system properties:

(let [properties (select-keys (into {} (System/getProperties))
                              ["os.arch" "os.name"])
      platform (apply format "%s (%s)" (vals properties))
      swt (case platform
            "Windows XP (x86)" '[org.eclipse/swt-win32-win32-x86 "3.5.2"]
            "Linux (x86)"      '[org.eclipse/swt-gtk-linux-x86 "3.5.2"])]
  (defproject alyra.mana-punk/character "1.0.0-SNAPSHOT"
    :description "FIXME: write"
    :dependencies [[org.clojure/clojure "1.2.0"]
                   [org.clojure/clojure-contrib "1.2.0"]
                   ~swt]
    :main alyra.mana-punk.character.core))