[#11] reader functions

.gitignore

@@ -2,3 +2,4 @@
 /target
 .lein-failures
 /pom.xml
+.lein-repl-history

README.md

@@ -276,6 +276,17 @@ these messages to `*out*` and `*err*`. Stderr from the pod is redirected to
  "err" "debug"}
 ```
 
+#### readers
+
+If `format` is `edn` then the pod may describe reader functions:
+
+``` clojure
+{"readers" {"my/tag" "clojure.core/identity"}}
+```
+
+so payloads containing tagged values like `#my/tag[1 2 3]` are read correctly as
+`[1 2 3]`.
+
 #### Error handling
 
 Responses may contain an `ex-message` string and `ex-data` payload string (JSON

src/babashka/pods/impl.clj

@@ -36,8 +36,9 @@
         chans (:chans pod)
         out-stream (:out pod)
         err-stream (:err pod)
+        readers (:readers pod)
         read-fn (case format
-                  :edn edn/read-string
+                  :edn #(edn/read-string {:readers readers} %)
                   :json #(cheshire/parse-string-strict % true))]
     (try
       (loop []
@@ -100,7 +101,7 @@
                           (println err))))
             (recur))))
       (catch Exception e
-        (binding [*out* err-stream]
+        (binding [*out* *err* #_err-stream]
           (prn e))))))
 
 (defn next-id []
@@ -151,9 +152,18 @@
       (let [[o _] (swap-vals! counter inc)]
         o))))
 
+(def bytes->symbol
+  (comp symbol bytes->string))
+
+(defn read-readers [reply resolve-fn]
+  (when-let [dict (get reply "readers")]
+    (let [dict-keys (map symbol (keys dict))
+          dict-vals (map (comp resolve-fn bytes->symbol) (vals dict))]
+      (zipmap dict-keys dict-vals))))
+
 (defn load-pod
   ([pod-spec] (load-pod pod-spec nil))
-  ([pod-spec {:keys [:remove-ns]}]
+  ([pod-spec {:keys [:remove-ns :resolve]}]
    (let [pod-spec (if (string? pod-spec) [pod-spec] pod-spec)
          pb (ProcessBuilder. ^java.util.List pod-spec)
          _ (.redirectError pb java.lang.ProcessBuilder$Redirect/INHERIT)
@@ -168,7 +178,8 @@
          reply (read stdout)
          format (-> (get reply "format") bytes->string keyword)
          ops (some->> (get reply "ops") keys (map keyword) set)
-         ;; pod-id (get-maybe-string reply "pod/id")
+         readers (when (identical? :edn format)
+                   (read-readers reply resolve))
          pod {:process p
               :pod-spec pod-spec
               :stdin stdin
@@ -178,7 +189,8 @@
               :ops ops
               :out *out*
               :err *err*
-              :remove-ns remove-ns}
+              :remove-ns remove-ns
+              :readers readers}
          _ (add-shutdown-hook! #(destroy pod))
          pod-namespaces (get reply "namespaces")
          pod-id (or (when-let [ns (first pod-namespaces)]

src/babashka/pods/jvm.clj

@@ -4,7 +4,14 @@
 (defn load-pod
   ([pod-spec] (load-pod pod-spec nil))
   ([pod-spec _opts]
-   (let [pod (impl/load-pod pod-spec {:remove-ns remove-ns})
+   (let [pod (impl/load-pod
+              pod-spec
+              {:remove-ns remove-ns
+               :resolve (fn [sym]
+                          (or (resolve sym)
+                              (intern
+                               (create-ns (symbol (namespace sym)))
+                               (symbol (name sym)))))})
          namespaces (:namespaces pod)]
      (doseq [[ns-sym v] namespaces]
        (binding [*ns* (load-string (format "(ns %s) *ns*" ns-sym))]

src/babashka/pods/sci.clj

@@ -10,17 +10,31 @@
        (let [env (:env ctx)
              pod (binding [*out* @sci/out
                            *err* @sci/err]
-                   (impl/load-pod pod-spec
+                   (impl/load-pod
-                                  {:remove-ns
+                    pod-spec
-                                   (fn [sym]
+                    {:remove-ns
-                                     (swap! env update :namespaces dissoc sym))}))
+                     (fn [sym]
+                       (swap! env update :namespaces dissoc sym))
+                     :resolve
+                     (fn [sym]
+                       (let [sym-ns (or (some-> (namespace sym)
+                                                symbol)
+                                        'clojure.core)
+                             sym-name (symbol (name sym))]
+                         (or (get-in @env [:namespaces sym-ns sym-name])
+                             (let [v (sci/new-var sym {:predefined true})]
+                               (swap! env assoc-in [:namespaces sym-ns sym-name]
+                                      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] 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))

test-pod/pod/test_pod.clj

@@ -58,6 +58,10 @@
                 (do (write {"format" (if (= format :json)
                                        "json"
                                        "edn")
+                            "readers" {"my/tag" "identity"
+                                       ;; NOTE: this function is defined later,
+                                       ;; which should be supported
+                                       "my/other-tag" "pod.test-pod/read-other-tag"}
                             "namespaces"
                             [{"name" "pod.test-pod"
                               "vars" (into [{"name" "add-sync"}
@@ -69,7 +73,13 @@
                                             {"name" "print-err"}
                                             {"name" "return-nil"}
                                             {"name" "do-twice"
-                                             "code" "(defmacro do-twice [x] `(do ~x ~x))"}]
+                                             "code" "(defmacro do-twice [x] `(do ~x ~x))"}
+                                            {"name" "reader-tag"}
+                                            ;; returns thing with other tag
+                                            {"name" "other-tag"}
+                                            ;; reads thing with other tag
+                                            {"name" "read-other-tag"
+                                             "code" "(defn read-other-tag [x] [x x])"}]
                                            dependents)}]
                             "ops" {"shutdown" {}}})
                     (recur))
@@ -134,7 +144,17 @@
                             (write
                              {"status" ["done"]
                               "id" id
-                              "value" "nil"}))
+                              "value" "nil"})
+                            pod.test-pod/reader-tag
+                            (write
+                             {"status" ["done"]
+                              "id" id
+                              "value" "#my/tag[1 2 3]"})
+                            pod.test-pod/other-tag
+                            (write
+                             {"status" ["done"]
+                              "id" id
+                              "value" "#my/other-tag[1]"}))
                           (recur))
                 :shutdown (System/exit 0))))))
       (catch Exception e

test-resources/test_program.clj

@@ -43,6 +43,9 @@
 
 (def x9 pod.test-pod/x9)
 
+(def tagged (pod/reader-tag))
+(def other-tagged (pod/other-tag))
+
 (pods/unload-pod pod-id)
 (def successfully-removed (nil? (find-ns 'pod.test-pod)))
 
@@ -58,4 +61,6 @@
  (:ex-message @error-result)
  (:ex-data @error-result)
  successfully-removed
- x9]
+ x9
+ tagged
+ other-tagged]

test/babashka/pods/test_common.clj

@@ -1,6 +1,5 @@
 (ns babashka.pods.test-common
   (:require [clojure.java.io :as io]
-            [clojure.string :as str]
             [clojure.test :refer [is]]))
 
 (def test-program (slurp (io/file "test-resources" "test_program.clj")))
@@ -16,12 +15,15 @@
                         "Illegal arguments / {:args (1 2 3)}"
                         nil
                         3
-                        "java.lang.String cannot be cast to java.lang.Number"
+                        #"cast"
                         {:args ["1" 2]}
                         true
-                        9] ret)]
+                        9
-    (if (string? expected)
+                        [1 2 3]
-      (str/includes? actual expected)
+                        [[1] [1]]]
-      (= expected actual)))
+               (concat ret (repeat ::nil)))]
+    (if (instance? java.util.regex.Pattern expected)
+      (is (re-find expected actual))
+      (is (= expected actual))))
   (is (= "(\"hello\" \"print\" \"this\" \"debugging\" \"message\")\n:foo\n:foo\n" (str out)))
   (is (= "(\"hello\" \"print\" \"this\" \"error\")\n" (str err))))