Identity monad

src/identity-monad.lfe

@@ -0,0 +1,11 @@
+(defmodule identity-monad
+  (behaviour monad)
+  (export (>>= 2)
+          (return 1)
+          (fail 1)))
+
+(defun >>= (x f)
+  (funcall f x))
+
+(defun return (x) x)
+(defun fail (x) (throw (tuple 'error x)))

test/unit/unit-identity-monad-tests.lfe

@@ -0,0 +1,20 @@
+(defmodule unit-identity-monad-tests
+  (export all)
+  (import
+    (from lfeunit-util
+      (check-failed-assert 2)
+      (check-wrong-assert-exception 2))))
+
+(include-lib "deps/lfeunit/include/lfeunit-macros.lfe")
+(include-lib "include/monads.lfe")
+(include-lib "include/monad-tests.lfe")
+
+(test-monad identity-monad)
+
+(deftest identity
+  (is-equal 'ok
+            (return identity-monad 'ok)))
+
+(deftest fail-with-error
+  (is-throw #(error value)
+            (fail identity-monad 'value)))