Support reader_tags.clj(c) (#1481)

CHANGELOG.md

@@ -11,6 +11,7 @@ A preview of the next release can be installed from
 
 - [#1473](https://github.com/babashka/babashka/issues/1473): make relative paths in bb.edn resolve relative to it ([@lispyclouds](https://github.com/lispyclouds))
 - Compatibility with `clojure.tools.namespace.repl/refresh` and `clojure.java.classpath`
+- Support reading tags from `data_readers.clj` and `data_readers.cljc`
 
 ## 1.1.172 (2023-01-23)
 

src/babashka/impl/deps.clj

@@ -92,7 +92,11 @@
                    args (concat args [(str "-A:" (str/join ":" (cons ":org.babashka/defaults" aliases)))])
                    bindings (cond->
                               {#'deps/*env* env
-                               #'deps/*extra-env* extra-env}
+                               #'deps/*extra-env* extra-env
+                               #'deps/*exit-fn* (fn
+                                                  ([_])
+                                                  ([_exit-code msg]
+                                                   (throw (Exception. msg))))}
                               deps-root (assoc #'deps/*dir* (str deps-root)))
                    cp (with-out-str (with-bindings bindings
                                       (apply deps/-main args)))

src/babashka/main.clj

@@ -56,6 +56,7 @@
    [clojure.edn :as edn]
    [clojure.java.io :as io]
    [clojure.string :as str]
+   [edamame.core :as edamame]
    [hf.depstar.uberjar :as uberjar]
    [sci.addons :as addons]
    [sci.core :as sci]
@@ -63,6 +64,7 @@
    [sci.impl.copy-vars :as sci-copy-vars]
    [sci.impl.io :as sio]
    [sci.impl.namespaces :as sci-namespaces]
+   [sci.impl.parser]
    [sci.impl.types :as sci-types]
    [sci.impl.unrestrict :refer [*unrestricted*]]
    [sci.impl.vars :as vars])
@@ -234,8 +236,7 @@ When no eval opts or subcommand is provided, the implicit subcommand is repl.")
  (clojure.repl/doc %1$s)
  true)" arg)))
       [nil 0]
-      [nil 1]))
+      [nil 1])))
-  ,)
 
 (defn print-run-help []
   (println (str/trim "
@@ -423,8 +424,7 @@ Use bb run --help to show this help output.
                   ;; 'fork (sci/copy-var sci/fork sci-ns)
                }
     'babashka.cli cli/cli-namespace
-       'babashka.http-client http-client-namespace
+    'babashka.http-client http-client-namespace}
-       }
     features/xml?  (assoc 'clojure.data.xml @(resolve 'babashka.impl.xml/xml-namespace)
                           'clojure.data.xml.event @(resolve 'babashka.impl.xml/xml-event-namespace)
                           'clojure.data.xml.tree @(resolve 'babashka.impl.xml/xml-tree-namespace))
@@ -650,13 +650,13 @@ Use bb run --help to show this help output.
                 opts-map (assoc opts-map :prn true)]
             (recur (next options)
                    (update opts-map :expressions (fnil conj []) (first options))))
-          ("--main", "-m",)
+          ("--main", "-m")
           (let [options (next options)]
             (assoc opts-map :main (first options)
                    :command-line-args (if (= "--" (second options))
                                         (nthrest options 2)
                                         (rest options))))
-          ("--exec", "-x",)
+          ("--exec", "-x")
           (let [options (next options)]
             (assoc opts-map :exec (first options)
                    :command-line-args (if (= "--" (second options))
@@ -780,6 +780,39 @@ Use bb run --help to show this help output.
       env-os-name-present? (not= env-os-name sys-os-name)
       env-os-arch-present? (not= env-os-arch sys-os-arch))))
 
+(def seen-urls (atom nil))
+
+(defn read-data-readers [url]
+  (edamame/parse-string (slurp url)
+                        {:read-cond :allow
+                         :features #{:bb :clj}
+                         :eof nil}))
+
+(defn readers-fn
+  "Lazy reading of data reader functions"
+  [ctx t]
+  (or (@core/data-readers t)
+      (default-data-readers t)
+      (when (simple-symbol? t)
+        (when-let [the-var (sci/resolve ctx t)]
+          (some-> the-var meta :sci.impl.record/map-constructor)))
+      (when-let [f @sci.impl.parser/default-data-reader-fn]
+        (fn [form]
+          (f t form)))
+      (let [;; urls is a vector for equality check
+            urls (vec (.getURLs ^java.net.URLClassLoader @cp/the-url-loader))
+            parsed-resources (or (get @seen-urls urls)
+                                 (let [^java.net.URLClassLoader cl @cp/the-url-loader
+                                       resources (concat (enumeration-seq (.getResources cl "data_readers.clj"))
+                                                         (enumeration-seq (.getResources cl "data_readers.cljc")))
+                                       parsed-resources (apply merge (map read-data-readers resources))
+                                       _ (swap! seen-urls assoc urls parsed-resources)]
+                                   parsed-resources))]
+        (when-let [var-sym (get parsed-resources t)]
+          (when-let [the-var (sci/resolve ctx var-sym)]
+            (sci/eval-form ctx (list 'clojure.core/var-set core/data-readers (list 'quote (assoc @core/data-readers t the-var))))
+            the-var)))))
+
 (defn exec [cli-opts]
   (with-bindings {#'*unrestricted* true
                   clojure.lang.Compiler/LOADER @cp/the-url-loader}
@@ -899,7 +932,8 @@ Use bb run --help to show this help output.
                   :uberscript uberscript
                   ;; :readers core/data-readers
                   :reify-fn reify-fn
-                  :proxy-fn proxy-fn}
+                  :proxy-fn proxy-fn
+                  :readers #(readers-fn (common/ctx) %)}
             opts (addons/future opts)
             sci-ctx (sci/init opts)
             _ (ctx-store/reset-ctx! sci-ctx)

test-resources/babashka/src_for_classpath_test/data_readers.clj

@@ -0,0 +1 @@
+{r/reverse reader/reversev}

test-resources/babashka/src_for_classpath_test/data_readers.cljc

@@ -0,0 +1 @@
+{r/distinct reader/distinctv}

test-resources/babashka/src_for_classpath_test/reader.clj

@@ -0,0 +1,7 @@
+(ns reader)
+
+(defn reversev [data]
+  (vec (reverse data)))
+
+(defn distinctv [data]
+  (vec (distinct data)))

test/babashka/classpath_test.clj

@@ -82,3 +82,8 @@
                  (.getResourceAsStream (clojure.lang.RT/baseLoader) \"foo.clj\")
                  (.getResources (clojure.lang.RT/baseLoader) \"foo.clj\")])")]
     (is (= [true true true] (edn/read-string results)))))
+
+(deftest reader-tag-test
+  (is (= [[3 2 1] [1 2 3]]
+         (bb nil "--classpath" "test-resources/babashka/src_for_classpath_test"
+             "(require 'reader) [#r/reverse [1 2 3] #r/distinct [1 1 2 3]]"))))