* lib/yaml.rb: switch default YAML engine to Psych, old syck engine

may be enabled via YAML::ENGINE.yamler = "syck". [ruby-core:36374]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31715 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Tue May 24 04:01:46 2011  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* lib/yaml.rb: switch default YAML engine to Psych, old syck engine
+	  may be enabled via YAML::ENGINE.yamler = "syck". [ruby-core:36374]
+
 Mon May 23 09:45:26 2011  Hiroshi Nakamura  <nahi@ruby-lang.org>
 
 	* include/ruby/defines.h (CASEFOLD_FILESYSTEM): Revert r30508. Forgot to

NEWS

@@ -149,6 +149,10 @@ with all sufficient information, see the ChangeLog file.
   * new logging directive:
     * %{remote}p for remote (client) port number.
 
+* yaml
+  * The default YAML engine is now Psych. You may downgrade to syck by setting
+    YAML::ENGINE.yamler = 'syck'.
+
 * zlib
   * new methods:
     * Zlib.deflate

lib/yaml.rb

@@ -30,6 +30,14 @@ module YAML
   ENGINE = YAML::EngineManager.new
 end
 
+begin
+  require 'psych'
+rescue LoadError
+  warn "#{caller[0]}:"
+  warn "It seems your ruby installation is missing psych (for YAML output)."
+  warn "To eliminate this warning, please install libyaml and reinstall your ruby."
+end
+
 engine = (!defined?(Syck) && defined?(Psych) ? 'psych' : 'syck')
 
 module Syck