class Regexp::Expression::Alternation

def <<(exp)
  @expressions.last << exp
end

def alternative(exp = nil)
  @expressions << (exp ? exp : Sequence.new)
end

def alternatives
  @expressions
end

def quantify(token, text, min = nil, max = nil, mode = :greedy)
  @expressions.last.last.quantify(token, text, min, max, mode)
end

def to_s
  @expressions.map{|e| e.to_s}.join('|')
end