fix #684: support print-method on records (#685)

src/sci/impl/io.cljc

@@ -2,12 +2,25 @@
   {:no-doc true}
   (:refer-clojure :exclude [pr prn pr-str prn-str print print-str println
                             newline flush with-out-str with-in-str read-line
-                            printf #?@(:cljs [string-print])])
+                            printf #?@(:cljs [string-print])
+                            print-method])
   (:require #?(:cljs [goog.string])
+            [sci.impl.records]
             [sci.impl.unrestrict :refer [*unrestricted*]]
             #?(:cljs [sci.impl.utils :as utils])
             [sci.impl.vars :as vars]))
 
+#?(:clj
+   (defmulti print-method (fn [x _writer]
+                            (if (instance? sci.impl.records.SciRecord x)
+                              (-> x meta :type)
+                              :default))))
+
+#?(:clj
+   (defmethod print-method :default
+     [x writer]
+     (clojure.core/print-method x writer)))
+
 #?(:clj (set! *warn-on-reflection* true))
 
 (defn core-dynamic-var

src/sci/impl/namespaces.cljc

@@ -834,7 +834,7 @@
    'pr-str (copy-core-var io/pr-str)
    'prn-str (copy-core-var io/prn-str)
    'print-str (copy-core-var #?(:cljs io/print-str :clj print-str))
-   #?@(:clj ['print-method (copy-core-var print-method)])
+   #?@(:clj ['print-method (copy-core-var io/print-method)])
    #?@(:clj ['print-dup (copy-core-var print-dup)])
    #?@(:clj ['printf (copy-core-var io/printf)])
    'with-out-str (macrofy 'with-out-str io/with-out-str)

test/sci/records_test.cljc

@@ -164,3 +164,8 @@
 (deftest roundtrip-test
   (let [prog "(ns foo) (defrecord A [x y z]) (str [#foo.A{:x 1 :y 2 :z 3} (read-string \"#foo.A{:x 1 :y 2 :z 3}\")])"]
     (is (= "[#foo.A{:x 1, :y 2, :z 3} #foo.A{:x 1, :y 2, :z 3}]" (tu/eval* prog {})))))
+
+#?(:clj
+   (deftest print-method-test
+     (let [prog "(ns foo) (defrecord A [x y z]) (defmethod print-method A [x writer] (.write writer \"<A>\")) (pr-str (->A 1))"]
+       (is (= "<A>" (tu/eval* prog {}))))))