add clojure.main/with-read-known

src/babashka/impl/clojure/main.clj

@@ -55,6 +55,13 @@ by default when a new command-line REPL is started."} repl-requires
   '[[clojure.repl :refer (source apropos pst dir doc find-doc)]
     [clojure.pprint :refer (pp pprint)]])
 
+(defmacro with-read-known
+  "Evaluates body with *read-eval* set to a \"known\" value,
+   i.e. substituting true for :unknown if necessary."
+  [& body]
+  `(binding [*read-eval* (if (= :unknown *read-eval*) true *read-eval*)]
+     ~@body))
+
 (defn repl
   "Generic, reusable, read-eval-print loop. By default, reads from *in*,
   writes to *out*, and prints exception summaries to *err*. If you use the

src/babashka/main.clj

@@ -385,6 +385,7 @@ Use bb run --help to show this help output.
                                           (repl/start-repl! (common/ctx) opts))) {:ns clojure-main-ns})
                    'with-bindings (sci/copy-var clojure-main/with-bindings clojure-main-ns)
                    'repl-caught (sci/copy-var repl/repl-caught clojure-main-ns)
+                   'with-read-known (sci/copy-var clojure-main/with-read-known clojure-main-ns)
                    'main main-var}
     'clojure.test t/clojure-test-namespace
     'clojure.math math-namespace

test/babashka/impl/clojure/main_test.clj

@@ -0,0 +1,18 @@
+(ns babashka.impl.clojure.main-test
+  (:require [babashka.test-utils :as tu]
+            [clojure.edn :as edn]
+            [clojure.test :as t :refer [deftest is testing]]))
+
+(def bb
+  (comp edn/read-string tu/bb))
+
+(deftest with-read-known-test
+  (testing ":unknown gets set to true"
+    (is (true? (bb nil (pr-str '(binding [*read-eval* :unknown]
+                                  (clojure.main/with-read-known *read-eval*)))))))
+  (testing "other values don't change"
+    (t/are [read-eval-value]
+      (= read-eval-value
+        (bb nil (str "(binding [*read-eval* " read-eval-value "]"
+                  " (clojure.main/with-read-known *read-eval*))")))
+      false true 5)))