1 files changed, 18 insertions, 0 deletions
diff --git a/lib/yaml.rb b/lib/yaml.rb
index eb0427a9d4..ff9e1a6344 100644
--- a/lib/yaml.rb
+++ b/lib/yaml.rb
@@ -1,3 +1,18 @@
+##
+# The YAML module allows you to use one of the two YAML engines that ship with
+# ruby.  By default Psych is used but the old and unmaintained Syck may be
+# chosen.
+#
+# See Psych or Syck for usage and documentation.
+#
+# To set the YAML engine to syck:
+#
+#   YAML::ENGINE.yamler = 'syck'
+#
+# To set the YAML engine back to psych:
+#
+#   YAML::ENGINE.yamler = 'psych'
+
 module YAML
   class EngineManager # :nodoc:
     attr_reader :yamler
@@ -27,6 +42,9 @@ module YAML
     end
   end
 
+  ##
+  # Allows changing the current YAML engine.  See YAML for details.
+
   ENGINE = YAML::EngineManager.new
 end