add ::di/service meta key

Co-authored-by: Gleb Eliseev <[email protected]>

src/darkleaf/di/core.clj

@@ -555,15 +555,28 @@
     obj))
 
 (defn- build-fn [variable deps]
-  (let [max-arity (->> variable
+  (let [service?  (-> variable meta ::service)
+        max-arity (->> variable
                        arglists
                        (map count)
-                       (reduce max 0) long)]
-    (case max-arity
-      0 (-> (variable)
-            (wrap-stop variable))
-      1 (-> (variable deps)
-            (wrap-stop variable))
+                       (reduce max 0)
+                       long)]
+    (cond
+      (and service? (= 0 max-arity))
+      variable
+
+      (and service? (= 1 max-arity))
+      (partial variable deps)
+
+      (= 0 max-arity)
+      (-> (variable)
+          (wrap-stop variable))
+
+      (= 1 max-arity)
+      (-> (variable deps)
+          (wrap-stop variable))
+
+      :else
       (partial variable deps))))
 
 (defn- var->factory-defn [variable]

test/darkleaf/di/tutorial/y_multi_arity_service_test.clj

@@ -23,3 +23,50 @@
     (t/is (= [::result {`a :a, `b :b} :a1   :a2]   (s)))
     (t/is (= [::result {`a :a, `b :b} :arg1 :a2]   (s :arg1)))
     (t/is (= [::result {`a :a, `b :b} :arg1 :arg2] (s :arg1 :arg2)))))
+
+;; other
+
+
+(comment
+  (defn ^::di/service xxx-service-0 []
+    (gensym))
+
+  ;; or?
+  (defn xxx-service-0
+    {::di/kind :service}
+    []
+    (gensym))
+
+  ,,,)
+
+
+(defn ^::di/service xxx-service-0 []
+  (gensym))
+
+(t/deftest xxx-service-0-test
+  (with-open [s (di/start `xxx-service-0)]
+    (t/is (not= (s) (s))))
+
+  ,,)
+
+
+(defn ^::di/service xxx-service-1 [-deps]
+  (gensym))
+
+(t/deftest xxx-service-1-test
+  (with-open [s (di/start `xxx-service-1)]
+    (t/is (not= (s) (s))))
+
+  ,,)
+
+
+(defn ^::di/service xxx-service-0-1
+  ([]
+   0)
+  ([-deps]
+   1))
+
+(t/deftest xxx-service-0-1-test
+  (with-open [s (di/start `xxx-service-0-1)]
+    (t/is (= 1 (s))))
+  ,,)