class Steep::AST::Namespace

def self.empty
  new(path: [], absolute: false)
end

def self.parse(string)
  if string.start_with?("::")
    new(path: string.split("::").drop(1).map(&:to_sym), absolute: true)
  else
    new(path: string.split("::").map(&:to_sym), absolute: false)
  end
end

def self.root
  new(path: [], absolute: true)
end

def +(other)
  if other.absolute?
    other
  else
    self.class.new(path: path + other.path, absolute: absolute?)
  end
end

def ==(other)
  other.is_a?(Namespace) && other.path == path && other.absolute? == absolute?
end

def absolute!
  self.class.new(path: path, absolute: true)
end

def absolute?
  @absolute
end

def append(component)
  self.class.new(path: path + [component], absolute: absolute?)
end

def empty?
  path.empty?
end

def hash
  self.class.hash ^ path.hash ^ absolute?.hash
end

def initialize(path:, absolute:)
  @path = path
  @absolute = absolute
end

def parent
  raise "Parent with empty namespace" if empty?
  self.class.new(path: path.take(path.size - 1), absolute: absolute?)
end

def relative?
  !absolute?
end

def to_s
  if empty?
    absolute? ? "::" : ""
  else
    s = path.join("::")
    absolute? ? "::#{s}::" : "#{s}::"
  end
end