class Regexp::Expression::Sequence

branches.
Used as the base class for the Alternation alternatives and Conditional
a whole subexpression.
quantifiers, as it applies them to its last element instead of itself as
A sequence of expressions. Differs from a Subexpressions by how it handles

def initialize(level, set_level, conditional_level) 

def initialize(level, set_level, conditional_level)
  super Regexp::Token.new(
    :expression,
    :sequence,
    '',
    nil, # ts
    nil, # te
    level,
    set_level,
    conditional_level
  )
end

def quantify(token, text, min = nil, max = nil, mode = :greedy) 

def quantify(token, text, min = nil, max = nil, mode = :greedy)
  offset = -1
  target = expressions[offset]
  while target and target.is_a?(FreeSpace)
    target = expressions[offset -= 1]
  end
  raise ArgumentError.new("No valid target found for '#{text}' " +
                          "quantifier") unless target
  target.quantify(token, text, min, max, mode)
end

def starts_at 

def starts_at
  @expressions.first.starts_at
end

def text 

def text
  to_s
end