ADD: Y-Combinator in Clojure

4 files changed, 28 insertions, 2 deletions

diff --git a/languages/c/clojure/README.md b/languages/c/clojure/README.md
index d84137b..cbeeb34 100644
--- a/languages/c/clojure/README.md
+++ b/languages/c/clojure/README.md
@@ -7,3 +7,5 @@ Sourced from: https://github.com/srodrigo/lambda-calculus-in-clojure
 Blog post by source author (Sergio Rodrigo):
 1. [Booleans in Clojure](https://srodrigo.me/lambda-calculus-in-clojure-part-1/)
 2. [Numerals in Clojure](https://srodrigo.me/lambda-calculus-in-clojure-part-2/)
+
+Blog post about [Y-Combinator in Clojure](https://blog.klipse.tech/lambda/2016/08/07/pure-y-combinator-clojure.html) by different author (Yehonathan Sharvit).
diff --git a/languages/c/clojure/lambda-core/src/y_combinator.clj b/languages/c/clojure/lambda-core/src/y_combinator.clj
new file mode 100644
index 0000000..c474fbf
--- /dev/null
+++ b/languages/c/clojure/lambda-core/src/y_combinator.clj
@@ -0,0 +1,9 @@
+(ns y-combinator)
+
+(def Y (fn [f]
+         ((fn [x]
+            (x x))
+          (fn [x]
+            (f (fn [y]
+                 ((x x) y)))))))
+
diff --git a/languages/c/clojure/lambda-core/test/test_runner.clj b/languages/c/clojure/lambda-core/test/test_runner.clj
index 038b818..a851d4c 100644
--- a/languages/c/clojure/lambda-core/test/test_runner.clj
+++ b/languages/c/clojure/lambda-core/test/test_runner.clj
@@ -1,7 +1,8 @@
 (ns test-runner
   (:require [clojure.test :as t]
             [numerals-test]
-            [booleans-test]))
+            [booleans-test]
+            [y-combinator-test]))
 
 (defn -main [& args]
-  (t/run-tests 'numerals-test 'booleans-test))
+  (t/run-tests 'numerals-test 'booleans-test 'y-combinator-test))
diff --git a/languages/c/clojure/lambda-core/test/y_combinator_test.clj b/languages/c/clojure/lambda-core/test/y_combinator_test.clj
new file mode 100644
index 0000000..c5396a0
--- /dev/null
+++ b/languages/c/clojure/lambda-core/test/y_combinator_test.clj
@@ -0,0 +1,14 @@
+(ns y-combinator-test
+  (:require [y-combinator :refer :all]
+            [clojure.test :refer :all]))
+
+
+(def factorial-gen (fn [func]
+                     (fn [n]
+                       (if (zero? n)
+                         1
+                         (* n (func (dec n)))))))
+
+(deftest λ-Y-Combinator
+  (testing "factorial"
+    (is (= ((Y factorial-gen) 19) 121645100408832000))))