* ext/psych/lib/psych/deprecated.rb: supporting detect_implicit method

* test/psych/test_deprecated.rb: ditto

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27478 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/psych/lib/psych.rb

@@ -241,6 +241,5 @@ module Psych
     attr_accessor :dump_tags
     attr_accessor :domain_types
   end
-
   # :startdoc:
 end

ext/psych/lib/psych/deprecated.rb

@@ -30,6 +30,12 @@ module Psych
     list.each(&block)
   end
 
+  def self.detect_implicit thing
+    warn "#{caller[0]}: detect_implicit is deprecated" if $VERBOSE
+    return '' unless String === thing
+    return 'null' if '' == thing
+    ScalarScanner.new.tokenize(thing).class.name.downcase
+  end
 end
 
 class Object

test/psych/test_deprecated.rb

@@ -163,5 +163,13 @@ module Psych
 
       assert_equal [["tag:ruby.yaml.org,2002:foo", "bar"]], types
     end
+
+    def test_detect_implicit
+      assert_equal '', Psych.detect_implicit(nil)
+      assert_equal '', Psych.detect_implicit(Object.new)
+      assert_equal '', Psych.detect_implicit(1.2)
+      assert_equal 'null', Psych.detect_implicit('')
+      assert_equal 'string', Psych.detect_implicit('foo')
+    end
   end
 end