add an example of polymorphic functions

KeenS · KeenS · commit 588cb6439b0b · 2022-09-21T10:04:50.000+09:00
diff --git a/ml_example/polymorphic_function.sml b/ml_example/polymorphic_function.sml
@@ -0,0 +1,3 @@
+fun id x = x
+val x = id 1
+val y = id false
