diff --git a/deps.edn b/deps.edn
index 8d1119f..85e11d9 100644
--- a/deps.edn
+++ b/deps.edn
@@ -4,7 +4,7 @@
  :aliases
  {:sci
   {:extra-deps
-   {borkdude/sci {:mvn/version "0.0.13-alpha.19"}}}
+   {borkdude/sci {:mvn/version "0.0.13-alpha.22"}}}
   :test
   {:extra-deps
    {test-runner
diff --git a/src/babashka/pods/impl.clj b/src/babashka/pods/impl.clj
index 6d6d968..d779535 100644
--- a/src/babashka/pods/impl.clj
+++ b/src/babashka/pods/impl.clj
@@ -27,6 +27,10 @@
   (-> (get m k)
       bytes->string))
 
+(defn get-maybe-string [m k]
+  (some-> (get m k)
+          bytes->string))
+
 (defn processor [pod]
   (let [stdout (:stdout pod)
         format (:format pod)
@@ -154,10 +158,13 @@
                                            bytes->string
                                            #(Boolean/parseBoolean %))
                             name-sym (symbol name)
-                            sym (symbol ns-name-str name)]
-                        (assoc m name-sym (fn [& args]
-                                            (let [res (invoke pod sym args async?)]
-                                              res)))))
+                            sym (symbol ns-name-str name)
+                            code (get-maybe-string var "code")]
+                        (assoc m name-sym
+                               (or code
+                                   (fn [& args]
+                                     (let [res (invoke pod sym args async?)]
+                                       res))))))
                     {}
                     vars))
          pod-namespaces (reduce (fn [namespaces namespace]
diff --git a/src/babashka/pods/jvm.clj b/src/babashka/pods/jvm.clj
index 355a279..2518ef9 100644
--- a/src/babashka/pods/jvm.clj
+++ b/src/babashka/pods/jvm.clj
@@ -7,9 +7,14 @@
    (let [pod (impl/load-pod pod-spec _opts)
          namespaces (:namespaces pod)]
      (doseq [[ns-sym v] namespaces]
-       (binding [*ns* (create-ns ns-sym)]
-         (dosync (commute @#'clojure.core/*loaded-libs* conj ns-sym)))
-       (doseq [[var-sym v] v]
-         (intern ns-sym var-sym v)))
+       (binding [*ns* (load-string (format "(ns %s) *ns*" ns-sym))]
+         (doseq [[var-sym v] v]
+           (cond
+             (ifn? v)
+             (do
+               (ns-unmap *ns* var-sym)
+               (intern ns-sym var-sym v))
+             (string? v)
+             (load-string v)))))
      (future (impl/processor pod))
      nil)))
diff --git a/src/babashka/pods/sci.clj b/src/babashka/pods/sci.clj
index af3c211..c1f06c0 100644
--- a/src/babashka/pods/sci.clj
+++ b/src/babashka/pods/sci.clj
@@ -12,7 +12,14 @@
                    (impl/load-pod pod-spec _opts))
              namespaces (:namespaces pod)
              env (:env ctx)]
-         (swap! env update :namespaces merge namespaces)
+         (doseq [[ns-name vars] namespaces
+                 :let [sci-ns (sci/create-ns ns-name)]]
+           (sci/binding [sci/ns sci-ns]
+             (doseq [[var-name var-value] vars]
+               (cond (ifn? var-value)
+                     (swap! env assoc-in [:namespaces ns-name var-name] var-value)
+                     (string? var-value)
+                     (sci/eval-string* ctx var-value)))))
          (sci/future (impl/processor pod))
          nil)))
     {:sci.impl/op :needs-ctx}))
diff --git a/test-pod/pod/test_pod.clj b/test-pod/pod/test_pod.clj
index 740d9d1..5c77067 100644
--- a/test-pod/pod/test_pod.clj
+++ b/test-pod/pod/test_pod.clj
@@ -45,21 +45,24 @@
                 op (read-string op)
                 op (keyword op)]
             (case op
-              :describe (do (write {"format" (if (= format :json)
-                                               "json"
-                                               "edn")
-                                    "namespaces"
-                                    [{"name" "pod.test-pod"
-                                      "vars" [{"name" "add-sync"}
-                                              {"name" "range-stream"
-                                               "async" "true"}
-                                              {"name" "assoc"}
-                                              {"name" "error"}
-                                              {"name" "print"}
-                                              {"name" "print-err"}
-                                              {"name" "return-nil"}]}]
-                                    "ops" {"shutdown" {}}})
-                            (recur))
+              :describe
+              (do (write {"format" (if (= format :json)
+                                     "json"
+                                     "edn")
+                          "namespaces"
+                          [{"name" "pod.test-pod"
+                            "vars" [{"name" "add-sync"}
+                                    {"name" "range-stream"
+                                     "async" "true"}
+                                    {"name" "assoc"}
+                                    {"name" "error"}
+                                    {"name" "print"}
+                                    {"name" "print-err"}
+                                    {"name" "return-nil"}
+                                    {"name" "do-twice"
+                                     "code" "(defmacro do-twice [x] `(do ~x ~x))"}]}]
+                          "ops" {"shutdown" {}}})
+                  (recur))
               :invoke (let [var (-> (get message "var")
                                     read-string
                                     symbol)
diff --git a/test/babashka/pods/jvm_test.clj b/test/babashka/pods/jvm_test.clj
index a8c1895..30df013 100644
--- a/test/babashka/pods/jvm_test.clj
+++ b/test/babashka/pods/jvm_test.clj
@@ -1,6 +1,6 @@
 (ns babashka.pods.jvm-test
-  (:require [babashka.pods.test-common :refer [test-program]]
-            [clojure.test :refer [deftest is]]))
+  (:require [babashka.pods.test-common :refer [test-program assertions]]
+            [clojure.test :refer [deftest]]))
 
 (deftest jvm-test
   (let [out (java.io.StringWriter.)
@@ -11,10 +11,4 @@
                     test-program)
                    (catch Exception e (prn e))))]
 
-    (is (= '[{:a 1, :b 2}
-             6
-             [1 2 3 4 5 6 7 8 9]
-             "Illegal arguments / {:args (1 2 3)}"
-             nil] ret))
-    (is (= "nil\n(\"hello\" \"print\" \"this\" \"debugging\" \"message\")\n" (str out)))
-    (is (= "(\"hello\" \"print\" \"this\" \"error\")\n" (str err)))))
+    (assertions out err ret)))
diff --git a/test/babashka/pods/sci_test.clj b/test/babashka/pods/sci_test.clj
index 407c24e..4666aff 100644
--- a/test/babashka/pods/sci_test.clj
+++ b/test/babashka/pods/sci_test.clj
@@ -1,8 +1,8 @@
 (ns babashka.pods.sci-test
   (:require [babashka.pods.sci :as pods]
-            [babashka.pods.test-common :refer [test-program]]
+            [babashka.pods.test-common :refer [test-program assertions]]
             [clojure.core.async :as async]
-            [clojure.test :refer [deftest is]]
+            [clojure.test :refer [deftest]]
             [sci.core :as sci]))
 
 (deftest sci-test
@@ -17,10 +17,4 @@
                              'clojure.core.async
                              {'<!! async/<!!}}}))]
 
-    (is (= '[{:a 1, :b 2}
-             6
-             [1 2 3 4 5 6 7 8 9]
-             "Illegal arguments / {:args (1 2 3)}"
-             nil] ret))
-    (is (= "nil\n(\"hello\" \"print\" \"this\" \"debugging\" \"message\")\n" (str out)))
-    (is (= "(\"hello\" \"print\" \"this\" \"error\")\n" (str err)))))
+    (assertions out err ret)))
diff --git a/test/babashka/pods/test_common.clj b/test/babashka/pods/test_common.clj
index 777f2d2..6840181 100644
--- a/test/babashka/pods/test_common.clj
+++ b/test/babashka/pods/test_common.clj
@@ -1,4 +1,5 @@
-(ns babashka.pods.test-common)
+(ns babashka.pods.test-common
+  (:require [clojure.test :refer [is]]))
 
 (def test-program "
 (require '[babashka.pods :as pods])
@@ -18,8 +19,18 @@
       (str (ex-message e) \" / \" (ex-data e)))))
 (pod.test-pod/print \"hello\" \"print\" \"this\" \"debugging\" \"message\")
 (pod.test-pod/print-err \"hello\" \"print\" \"this\" \"error\")
+(pod/do-twice (prn :foo))
 [(pod/assoc {:a 1} :b 2)
  (pod.test-pod/add-sync 1 2 3)
   @stream-results
   ex-result
   (pod.test-pod/return-nil)]")
+
+(defn assertions [out err ret]
+  (is (= '[{:a 1, :b 2}
+           6
+           [1 2 3 4 5 6 7 8 9]
+           "Illegal arguments / {:args (1 2 3)}"
+           nil] ret))
+  (is (= "nil\n(\"hello\" \"print\" \"this\" \"debugging\" \"message\")\n:foo\n:foo\n" (str out)))
+  (is (= "(\"hello\" \"print\" \"this\" \"error\")\n" (str err))))