class Range
  include Enumerable

  `def._isRange = true;`

  attr_reader :begin, :end

  def initialize(first, last, exclude = false)
    @begin   = first
    @end     = last
    @exclude = exclude
  end

  def ==(other)
    %x{
      if (!other._isRange) {
        return false;
      }

      return self.exclude === other.exclude &&
             self.begin   ==  other.begin &&
             self.end     ==  other.end;
    }
  end

  # FIXME: currently hardcoded to assume range holds numerics
  def ===(obj)
    include?(obj)
  end

  def cover?(value)
    @begin <= value && (@exclude ? value < @end : value <= @end)
  end

  alias last end

  def each(&block)
    return enum_for :each unless block_given?

    current = @begin
    last    = @end

    while current < last
      yield current

      current = current.succ
    end

    yield current if !@exclude && current == last

    self
  end

  def eql?(other)
    return false unless Range === other

    @exclude === other.exclude_end? &&
    @begin.eql?(other.begin) &&
    @end.eql?(other.end)
  end

  def exclude_end?
    @exclude
  end

  alias first begin

  # FIXME: currently hardcoded to assume range holds numerics
  def include?(obj)
    cover?(obj)
  end

  # FIXME: currently hardcoded to assume range holds numerics
  def max
    if block_given?
      super
    else
      `#@exclude ? #@end - 1 : #@end`
    end
  end

  def min
    if block_given?
      super
    else
      @begin
    end
  end

  alias member? include?

  def step(n = 1)
    raise NotImplementedError
  end

  def to_s
    `#{@begin.inspect} + (#@exclude ? '...' : '..') + #{@end.inspect}`
  end

  alias inspect to_s
end