(defn eval-in-project
  "Executes form in an isolated classloader with the classpath and compile path
  set correctly for the project. Pass in a handler function to have it called
  with the java task right before executing if you need to customize any of its
  properties (classpath, library-path, etc)."
  [project form & [handler skip-auto-compile]]
  (when (and (not skip-auto-compile)
             (empty? (.list (file (:compile-path project)))))
    (binding [*silently* true]
      (compile project)))
  (when (empty? (find-lib-jars project))
    (deps project))
  (let [java (Java.)
        native-path (or (:native-path project)
                        (find-native-lib-path project))]
    (.setProject java lancet/ant-project)
    (.addSysproperty java (doto (Environment$Variable.)
                            (.setKey "clojure.compile.path")
                            (.setValue (:compile-path project))))
    (when native-path
      (.addSysproperty java (doto (Environment$Variable.)
                              (.setKey "java.library.path")
                              (.setValue (cond
                                          (= java.io.File (class native-path))
                                          (.getAbsolutePath native-path)
                                          (fn? native-path) (native-path)
                                          :default native-path)))))
    (.setClasspath java (apply make-path (get-classpath project)))
    (.setFailonerror java true)
    (.setFork java true)
    (doseq [arg (get-jvm-args project)]
      (when-not (re-matches #"^-Xbootclasspath.+" arg)
        (.setValue (.createJvmarg java) arg)))
    (.setClassname java "clojure.main")
    (.setValue (.createArg java) "-e")
    (let [cp (str (.getClasspath (.getCommandLine java)))
          form `(do (def ~'*classpath* ~cp)
                    (set! ~'*warn-on-reflection*
                          ~(:warn-on-reflection project))
                    ~form)]
      (.setValue (.createArg java) (prn-str form)))
    ;; to allow plugins and other tasks to customize
    (when handler (handler java))
    (.executeJava java)))