JSON string to ruby hash using RubyMotion

hash_to_json_rubymotion.rb

# https://github.com/rubymotion/BubbleWrap/blob/master/motion/core/json.rb
# Handles JSON encoding and decoding in a similar way Ruby 1.9 does.
module JSON
  class ParserError < StandardError; end

  # Parses a string or data object and converts it in data structure.
  #
  # @param [String, NSData] str_data the string or data to serialize.
  # @raise [ParserError] If the parsing of the passed string/data isn't valid.
  # @return [Hash, Array, NilClass] the converted data structure, nil if the incoming string isn't valid.
  #
  # TODO: support options like the C Ruby module does
  def self.parse(str_data)
    return nil unless str_data
    data = str_data.respond_to?('dataUsingEncoding:') ? str_data.dataUsingEncoding(NSUTF8StringEncoding) : str_data
    opts = NSJSONReadingMutableContainers | NSJSONReadingMutableLeaves | NSJSONReadingAllowFragments
    error = Pointer.new(:id)
    obj = NSJSONSerialization.JSONObjectWithData(data, options: opts, error: error)
    raise ParserError, error[0].description if error[0]
    if block_given?
      yield obj
    else
      obj
    end
  end

  def self.generate(obj)
    NSJSONSerialization.dataWithJSONObject(obj, options: 0, error: nil).to_str
  end
end