add-at, take 1

add_at.clj

;; non-working add-at
(require '[boot.core :as core]
         '[boot.tmpdir :as tmpd]
         '[clojure.java.io :as io])

(deftask add-at
  "Like sift :add-*, but lets you make a dest path in fileset"
  [r rolekey ROLEKEY kw "rolekey"
   s source SOURCE file "source path in project"
   d dest DEST file "dest path in fileset"]
  (fn [next-task]
    (fn [fileset]
      (next-task (tmpd/add fileset
                           (io/file
                            (#'core/get-add-dir fileset #{rolekey})
                            dest)
                           source
                           nil)))))

(boot (add-at :rolekey :asset
              :source (io/file "foo")
              :dest (io/file "bar"))
      (target))
;; AssertionError Assert failed: dest-dir not in dir set (/Users/stu/.boot/cache/tmp/meta/datomic-dev/jcp/-rcsl8f/bar)
;; ((set (map file dirs)) dest-dir)  boot.tmpdir.TmpFileSet (tmpdir.clj:276)