Merge pull request scala#497 from SethTisue/remove-inappropriate-app-reference

SethTisue · SethTisue · commit abb60a1a2fec · 2016-03-01T15:07:40.000+01:00
remove inappropriate warning about App
diff --git a/tutorials/tour/polymorphic-methods.md b/tutorials/tour/polymorphic-methods.md
@@ -15,17 +15,13 @@ Methods in Scala can be parameterized with both values and types. Like on the cl
 
 Here is an example:
 
-    object PolyTest extends App {
-      def dup[T](x: T, n: Int): List[T] =
-        if (n == 0)
-          Nil
-        else
-          x :: dup(x, n - 1)
+    def dup[T](x: T, n: Int): List[T] =
+      if (n == 0)
+        Nil
+      else
+        x :: dup(x, n - 1)
 
-      println(dup[Int](3, 4))
-      println(dup("three", 3))
-    }
+    println(dup[Int](3, 4))
+    println(dup("three", 3))
 
-Method `dup` in object `PolyTest` is parameterized with type `T` and with the value parameters `x: T` and `n: Int`. When method `dup` is called, the programmer provides the required parameters _(see line 8 in the program above)_, but as line 9 in the program above shows, the programmer is not required to give actual type parameters explicitly. The type system of Scala can infer such types. This is done by looking at the types of the given value parameters and at the context where the method is called.
-
-Please note that the trait `App` is designed for writing short test programs, but should be avoided for production code (for Scala versions 2.8.x and earlier) as it may affect the ability of the JVM to optimize the resulting code; please use `def main()` instead.
+Method `dup` is parameterized with type `T` and with the value parameters `x: T` and `n: Int`. In the first call to `dup`, the programmer provides the required parameters, but as the following line shows, the programmer is not required to give actual type parameters explicitly. The type system of Scala can infer such types. This is done by looking at the types of the given value parameters and at the context where the method is called.
