module TOML::BasicString

def self.decode_unicode(str)
  [str[2..-1].to_i(16)].pack('U')
end

def self.parse_error(m)
  fail ParseError.new "Escape sequence #{m} is reserved"
end

def self.transform_escaped_chars(str)
  str.gsub(/\\(u[\da-fA-F]{4}|U[\da-fA-F]{8}|.)/) do |m|
    if m.size == 2
      SPECIAL_CHARS[m] || parse_error(m)
    else
      decode_unicode(m).force_encoding('UTF-8')
    end
  end
end

def value
  aux = TOML::BasicString.transform_escaped_chars first.value
  aux[1...-1]
end