class Regexp::Parser

def sequence_operation(klass, token)
  unless node.instance_of?(klass)
    operator = klass.new(token, active_opts)
    sequence = operator.add_sequence(active_opts, { ts: token.ts })
    sequence.expressions = node.expressions
    node.expressions = []
    nest(operator)
  end
  node.add_sequence(active_opts, { ts: token.te })
end