* ext/psych/lib/psych/visitors/to_ruby.rb: fixing merge key support

when multiple merge keys are specified.
* test/psych/test_merge_keys.rb: tests for multi-merge key support

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@30630 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,10 @@
+Sat Jan 22 11:49:55 2011  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* ext/psych/lib/psych/visitors/to_ruby.rb: fixing merge key support
+	  when multiple merge keys are specified.
+
+	* test/psych/test_merge_keys.rb: tests for multi-merge key support
+	
 Sat Jan 22 11:33:04 2011  Aaron Patterson <aaron@tenderlovemaking.com>
 
 	* ext/psych/lib/psych/visitors/to_ruby.rb: merge keys are actually

ext/psych/lib/psych/visitors/to_ruby.rb

@@ -187,8 +187,17 @@ module Psych
           o.children.each_slice(2) { |k,v|
             key = accept(k)
 
-            if key == '<<' && Nodes::Alias === v
-              hash.merge! accept(v)
+            if key == '<<'
+              case v
+              when Nodes::Alias
+                hash.merge! accept(v)
+              when Nodes::Sequence
+                accept(v).reverse_each do |value|
+                  hash.merge! value
+                end
+              else
+                hash[key] = accept(v)
+              end
             else
               hash[key] = accept(v)
             end

test/psych/test_merge_keys.rb

@@ -17,5 +17,56 @@ bar:
         "bar" => { "hello" => "world", "baz" => "boo" } }
       assert_equal hash, Psych.load(yaml)
     end
+
+    def test_multiple_maps
+      yaml = <<-eoyaml
+---
+- &CENTER { x: 1, y: 2 }
+- &LEFT { x: 0, y: 2 }
+- &BIG { r: 10 }
+- &SMALL { r: 1 }
+
+# All the following maps are equal:
+
+- # Merge multiple maps
+  << : [ *CENTER, *BIG ]
+  label: center/big
+      eoyaml
+
+      hash = {
+        'x' => 1,
+        'y' => 2,
+        'r' => 10,
+        'label' => 'center/big'
+      }
+
+      assert_equal hash, Psych.load(yaml)[4]
+    end
+
+    def test_override
+      yaml = <<-eoyaml
+---
+- &CENTER { x: 1, y: 2 }
+- &LEFT { x: 0, y: 2 }
+- &BIG { r: 10 }
+- &SMALL { r: 1 }
+
+# All the following maps are equal:
+
+- # Override
+  << : [ *BIG, *LEFT, *SMALL ]
+  x: 1
+  label: center/big
+      eoyaml
+
+      hash = {
+        'x' => 1,
+        'y' => 2,
+        'r' => 10,
+        'label' => 'center/big'
+      }
+
+      assert_equal hash, Psych.load(yaml)[4]
+    end
   end
 end