module Tins::MethodDescription

def description(style: :namespace)
  valid_styles = %i[ namespace name parameters ]
  valid_styles.include?(style) or
    raise ArgumentError, "style has to be one of #{valid_styles * ', '}"
  result = ''
  if style == :namespace
    if owner <= Module
      result << receiver.to_s << '.' # XXX Better to use owner here as well?
    else
      result << owner.name.to_s << '#'
    end
  end
  if %i[ namespace name ].include?(style)
    result << name.to_s << '('
  end
  if respond_to?(:parameters)
    generated_name = 'x0'
    result << parameters.map { |p_type, p_name|
      p_name ||= generated_name.succ!.dup
      case p_type
      when :block
        "&#{p_name}"
      when :rest
        "*#{p_name}"
      when :keyrest
        "**#{p_name}"
      when :req
        p_name
      when :opt
        "#{p_name}=?"
      when :key
        "#{p_name}:?"
      when :keyreq
        "#{p_name}:"
      else
        [ p_name, p_type ] * ':'
      end
    } * ','
  else
    result << arity.to_s
  end
  if %i[ namespace name ].include?(style)
    result << ')'
  end
  result
end