Crystal .cycle Recycle after finish looping

Question

so in my case

def dynamic_data()
  data = [] of String
  # some data from db
  # data << db["somekey"].to_s
  return data
end

dynamic_data().cycle do |d|
  # some stuff
  puts d
end

My data reaches more than 500 row and will continue to grow and increase, how to make cycle finishing loop first, then reload new data again from function, or there is other method ? , thanks

Answer 1

how to make cycle finishing loop first

There is no way to make Array#cycle finishing, since it is explicitly designed to run forever (unless break is called, but this is unlikely what you are looking for).

If I properly understood your intent, you are trying to handle incoming portions of data. To do so, one needs more sophisticated handling, like:

class DataHandler
  def initialize
    @data = []
  end
  def data()
    @data.tap(&:clear)
  end
  def data!(new_data)
    @data << new_data
  end
end

data_handler = DataHandler.new

loop do
  break "empty data" if data_handler.data.empty?
  puts data_handler.data
end

---

Or, as pointed out in comments by Jonne Haß, using yield:

def dynamic_data()
  data = []
  loop do
    data << new_data
    yield data.tap(&:clear) if data.size > 100
  end
end

dynamic_data do
  puts d
end