1 files changed, 68 insertions, 0 deletions
diff --git a/ext/psych/lib/psych/coder.rb b/ext/psych/lib/psych/coder.rb
new file mode 100644
index 0000000000..79e46dab1b
--- /dev/null
+++ b/ext/psych/lib/psych/coder.rb
@@ -0,0 +1,68 @@
+module Psych
+  ###
+  # If an object defines +encode_with+, then an instance of Psych::Coder will
+  # be passed to the method when the object is being serialized.  The Coder
+  # automatically assumes a Psych::Nodes::Mapping is being emitted.  Other
+  # objects like Sequence and Scalar may be emitted if +seq=+ or +scalar=+ are
+  # called, respectively.
+  class Coder
+    attr_accessor :tag, :style, :implicit
+    attr_reader   :type, :map, :scalar, :seq
+
+    def initialize tag
+      @map        = {}
+      @seq        = []
+      @implicit   = false
+      @type       = :map
+      @tag        = tag
+      @style      = Psych::Nodes::Mapping::BLOCK
+      @scalar     = nil
+    end
+
+    # Emit a scalar with +value+ and +tag+
+    def represent_scalar tag, value
+      self.tag    = tag
+      self.scalar = value
+    end
+
+    # Emit a sequence with +list+ and +tag+
+    def represent_seq tag, list
+      @tag = tag
+      self.seq = list
+    end
+
+    # Emit a sequence with +map+ and +tag+
+    def represent_map tag, map
+      @tag = tag
+      self.map = map
+    end
+
+    # Emit a scalar with +value+
+    def scalar= value
+      @type   = :scalar
+      @scalar = value
+    end
+
+    # Emit a map with +value+
+    def map= map
+      @type = :map
+      @map  = map
+    end
+
+    def []= k, v
+      @type = :map
+      @map[k] = v
+    end
+
+    def [] k
+      @type = :map
+      @map[k]
+    end
+
+    # Emit a sequence of +list+
+    def seq= list
+      @type = :seq
+      @seq  = list
+    end
+  end
+end