adding alias nodes

4 files changed, 31 insertions, 1 deletions

diff --git a/lib/psych.rb b/lib/psych.rb
index aaec4a7..df5486a 100644
--- a/lib/psych.rb
+++ b/lib/psych.rb
@@ -4,6 +4,7 @@ require 'psych/nodes/document'
 require 'psych/nodes/sequence'
 require 'psych/nodes/scalar'
 require 'psych/nodes/mapping'
+require 'psych/nodes/alias'
 
 require 'psych/handler'
 require 'psych/tree_builder'
diff --git a/lib/psych/nodes/alias.rb b/lib/psych/nodes/alias.rb
new file mode 100644
index 0000000..b697cc1
--- /dev/null
+++ b/lib/psych/nodes/alias.rb
@@ -0,0 +1,15 @@
+module Psych
+  module Nodes
+    ###
+    # This class represents a {YAML Alias}[http://yaml.org/spec/1.1/#alias].
+    # It points to an +anchor+
+    class Alias < Psych::Nodes::Node
+      # The anchor this alias links to
+      attr_accessor :anchor
+
+      def initialize anchor
+        @anchor = anchor
+      end
+    end
+  end
+end
diff --git a/lib/psych/tree_builder.rb b/lib/psych/tree_builder.rb
index 6a10354..d9c7c5d 100644
--- a/lib/psych/tree_builder.rb
+++ b/lib/psych/tree_builder.rb
@@ -30,6 +30,7 @@ module Psych
         end
 
         def end_#{node.downcase}(*args)
+          super
           @stack.pop
         end
       }
@@ -44,5 +45,10 @@ module Psych
       super
       @stack.last.children << Nodes::Scalar.new(*args)
     end
+
+    def alias(*args)
+      super
+      @stack.last.children << Nodes::Alias.new(*args)
+    end
   end
 end
diff --git a/test/psych/test_tree_builder.rb b/test/psych/test_tree_builder.rb
index 0b51a10..552caed 100644
--- a/test/psych/test_tree_builder.rb
+++ b/test/psych/test_tree_builder.rb
@@ -12,7 +12,7 @@ module Psych
   bar : &A !!str baz,
   boo : *A
 }
-- baz
+- *A
       eoyml
       @tree = @parser.handler.root
     end
@@ -65,5 +65,13 @@ module Psych
 
       assert_instance_of Nodes::Mapping, map
     end
+
+    def test_alias
+      doc = @tree.children.first
+      seq = doc.children.first
+      al  = seq.children[2]
+      assert_instance_of Nodes::Alias, al
+      assert_equal 'A', al.anchor
+    end
   end
 end