class Psych::Visitors::Emitter

def initialize io, options = {}
  opts = [:indentation, :canonical, :line_width].find_all { |opt|
    options.key?(opt)
  }
  if opts.empty?
    @handler = Psych::Emitter.new io
  else
    du = Handler::DumperOptions.new
    opts.each { |option| du.send :"#{option}=", options[option] }
    @handler = Psych::Emitter.new io, du
  end
end

def visit_Psych_Nodes_Alias o
  @handler.alias o.anchor
end

def visit_Psych_Nodes_Document o
  @handler.start_document o.version, o.tag_directives, o.implicit
  o.children.each { |c| accept c }
  @handler.end_document o.implicit_end
end

def visit_Psych_Nodes_Mapping o
  @handler.start_mapping o.anchor, o.tag, o.implicit, o.style
  o.children.each { |c| accept c }
  @handler.end_mapping
end

def visit_Psych_Nodes_Scalar o
  @handler.scalar o.value, o.anchor, o.tag, o.plain, o.quoted, o.style
end

def visit_Psych_Nodes_Sequence o
  @handler.start_sequence o.anchor, o.tag, o.implicit, o.style
  o.children.each { |c| accept c }
  @handler.end_sequence
end

def visit_Psych_Nodes_Stream o
  @handler.start_stream o.encoding
  o.children.each { |c| accept c }
  @handler.end_stream
end