lazy namespaces experiment

src/babashka/pods/sci.clj

@@ -7,7 +7,19 @@
     (fn
       ([ctx pod-spec] (load-pod ctx pod-spec nil))
       ([ctx pod-spec _opts]
-       (let [env (:env ctx)
+       (let [ns-load-fns (atom {})
+             load-fn (fn load-fn [{:keys [:namespace]}]
+                       (when-let [f (get @ns-load-fns namespace)]
+                         (f)
+                         ;; return empty source, for sci to evaluate
+                         ""))
+             env (:env ctx)
+             prev-load-fn (:load-fn @env)
+             new-load-fn (fn [m]
+                           (or (load-fn m)
+                               (when prev-load-fn
+                                 (prev-load-fn m))))
+             _ (swap! env assoc :load-fn new-load-fn)
              pod (binding [*out* @sci/out
                            *err* @sci/err]
                    (impl/load-pod
@@ -27,16 +39,16 @@
                                       v)
                                v))))}))
              namespaces (:namespaces pod)]
-         (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]
-                            (sci/new-var
-                             (symbol (str ns-name) (str var-name)) var-value))
-                     (string? var-value)
-                     (sci/eval-string* ctx var-value)))))
+         (doseq [[ns-name vars] namespaces]
+           (swap! ns-load-fns assoc ns-name
+                  #(sci/binding [sci/ns (sci/create-ns ns-name)]
+                     (doseq [[var-name var-value] vars]
+                       (cond (ifn? var-value)
+                             (swap! env assoc-in [:namespaces ns-name var-name]
+                                    (sci/new-var
+                                     (symbol (str ns-name) (str var-name)) var-value))
+                             (string? var-value)
+                             (sci/eval-string* ctx var-value))))))
          (sci/future (impl/processor pod))
          {:pod/id (:pod-id pod)})))
     {:sci.impl/op :needs-ctx}))