From 989058e4d7866ee5fb29c1297aac950c864fc182 Mon Sep 17 00:00:00 2001
From: Flaviu Tamas <tamasflaviu@gmail.com>
Date: Tue, 26 May 2015 16:00:15 -0400
Subject: [PATCH] Add subtype test

---
 content/oop.md | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/content/oop.md b/content/oop.md
index 2e3870c..9edbdd7 100644
--- a/content/oop.md
+++ b/content/oop.md
@@ -38,3 +38,19 @@ woof
 meow
 10
 ```
+
+## Testing subtypes
+
+It is also possible to check if an object is of a given subtype with the `of` keyword. For example,
+
+``` nimrod
+echo(animals[0] of Dog)
+echo(animals[0] of Cat)
+echo(animals[0] of Animal)
+```
+``` console
+$ nim c -r of_op.nim
+true
+false
+true
+```