Support hashCode on deftype (#1017)

Author: borkdude

CHANGELOG.md

@@ -10,6 +10,10 @@ SCI is used in [babashka](https://github.com/babashka/babashka),
 [joyride](https://github.com/BetterThanTomorrow/joyride/) and many
 [other](https://github.com/babashka/sci#projects-using-sci) projects.
 
+## Unreleased
+
+- Support `hashCode` on `deftype`
+
 ## 0.11.50 (2025-12-23)
 
 - Add support for `:refer-global` and `:require-global`

src/sci/impl/deftype.cljc

@@ -35,6 +35,12 @@
      (defmethod equals :default [this other]
        (identical? this other))))
 
+#?(:clj
+   (do
+     (defmulti hashCode types/type-impl)
+     (defmethod hashCode :default [this]
+       (System/identityHashCode this))))
+
 (defn clojure-str [v]
   ;; #object[user.Foo 0x743e63ce "user.Foo@743e63ce"]
   (let [n (types/type-impl v)]
@@ -53,6 +59,8 @@
     (to-string this))
   #?(:clj (equals [this other]
                   (sci.impl.deftype/equals this other)))
+  #?(:clj (hashCode [this]
+                    (sci.impl.deftype/hashCode this)))
 
   sci.impl.types/SciTypeInstance
   (-get-type [_]

src/sci/impl/namespaces.cljc

@@ -837,7 +837,8 @@
   {:obj (sci.lang/->Namespace 'sci.impl.deftype nil)
    :private true
    'toString sci.impl.deftype/to-string
-   #?@(:clj ['equals sci.impl.deftype/equals])
+   #?@(:clj ['equals sci.impl.deftype/equals
+             'hashCode sci.impl.deftype/hashCode])
    '-create-type -create-type
    '->type-impl sci.impl.deftype/->type-impl
    '-inner-impl sci.impl.types/getVal

test/sci/records_test.cljc test/sci/defrecords_and_defype_test.cljctest/sci/records_test.cljc renamed to test/sci/defrecords_and_defype_test.cljc

@@ -1,4 +1,4 @@
-(ns sci.records-test
+(ns sci.defrecords-and-defype-test
   (:require
     [clojure.string :as str]
     [clojure.test :refer [are deftest is testing]]
@@ -223,7 +223,9 @@
   (is (true? (tu/eval* "(deftype Foo []) (instance? Foo (->Foo))" {})))
   (is (true? (tu/eval* "(ns bar) (deftype Foo []) (ns foo (:import [bar Foo])) (instance? Foo (Foo.))" {})))
   (is (= "dude" (tu/eval* "(deftype Dude [] Object (toString [_] \"dude\")) (str (->Dude))" {})))
-  #?(:clj (is (= [true false] (tu/eval* "(deftype Dude [x] Object (toString [_] (str x)) (equals [this other] (= (str this) (str other)))) [(= (->Dude 1) (->Dude 1)) (= (->Dude 1) (->Dude 2))]" {})))))
+  #?(:clj (is (= [true false] (tu/eval* "(deftype Dude [x] Object (toString [_] (str x)) (equals [this other] (= (str this) (str other)))) [(= (->Dude 1) (->Dude 1)) (= (->Dude 1) (->Dude 2))]" {}))))
+  #?(:clj (is (true? (tu/eval* "(deftype Dude [x] Object (hashCode [_] 1))
+(deftype Dude2 [x]) (and (= 1 (hash (Dude. 1337))) (not= 1 (hash (Dude2.))))" {})))))
 
 (deftest equiv-test
   (let [prog "(defrecord Foo [a]) (defrecord Bar [a]) [(= (->Foo 1) (->Foo 1)) (= (->Foo 1) (->Bar 1)) (= (->Foo 1) {:a 1})]"]

test/sci/test_runner.cljs

@@ -14,7 +14,7 @@
             [sci.parse-test]
             [sci.protocols-test]
             [sci.read-test]
-            [sci.records-test]
+            [sci.defrecords-and-defype-test]
             [sci.reify-test]
             [sci.repl-test]
             [sci.test-utils :refer [planck-env?]]