CSV::Parser#prepare_quote_character

# File tmp/rubies/ruby-3.1.3/lib/csv/parser.rb, line 477
def prepare_quote_character
  @quote_character = @options[:quote_character]
  if @quote_character.nil?
    @escaped_quote_character = nil
    @escaped_quote = nil
  else
    @quote_character = @quote_character.to_s.encode(@encoding)
    if @quote_character.length != 1
      message = ":quote_char has to be nil or a single character String"
      raise ArgumentError, message
    end
    @double_quote_character = @quote_character * 2
    @escaped_quote_character = Regexp.escape(@quote_character)
    @escaped_quote = Regexp.new(@escaped_quote_character)
  end
end