class Psych::Visitors::YAMLTree

def initialize emitter, ss, options
  super()
  @started    = false
  @finished   = false
  @emitter    = emitter
  @st         = Registrar.new
  @ss         = ss
  @options    = options
  @line_width = options[:line_width]
  if @line_width && @line_width < 0
    if @line_width == -1
      # Treat -1 as unlimited line-width, same as libyaml does.
      @line_width = nil
    else
      fail(ArgumentError, "Invalid line_width #{@line_width}, must be non-negative or -1 for unlimited.")
    end
  end
  @coders     = []
  @dispatch_cache = Hash.new do |h,klass|
    method = "visit_#{(klass.name || '').split('::').join('_')}"
    method = respond_to?(method) ? method : h[klass.superclass]
    raise(TypeError, "Can't dump #{target.class}") unless method
    h[klass] = method
  end
end