How to rewrite recursion in a more ruby way

Question

def get_all_friends(uid, client)
  friends = client.friendships.friends(uid: uid)
  total = friends.total_number
  get_friends(total, 0, uid, client)
end

def get_friends(total, cursor, uid, client)
  left = total
  count = [200, left].min

  friends = client.friendships.friends(uid: uid, count: count, cursor: cursor)
  left -= count
  next_cursor = friends.next_cursor

  return friends if (left == 0 || next_cursor == 0)

  more_firends = get_friends(left, next_cursor, uid, client)
  more_firends.users << friends.users
  return more_firends
end

get_all_friends(uid, observer.client).users.map do |info|
  user = User.find_or_create_by_uid_and_name(uid: info.id, name: info.name)
  follow(user)
  user
end

This code is written in a functional style. Maybe there is a more natural way to structure it with Block.

And how can I reuse the code when client.friendships.friends(uid: uid, count: count, cursor: cursor) differs?

---

Update:

I reconstruct the code. It now looks more clean and general.

def get_all_friends(client, uid)
  fetch_all do |count, cursor|
    client.friendships.friends(uid: uid, count: count, cursor: cursor)
  end
end

def fetch_all(&fetch_proc)
  res = fetch_proc.call(10, 0)
  total = res.total_number
  return res if total <= 10
  fetch(total, 0, &fetch_proc)
end

def fetch(total, cursor, &fetch_proc)
  left = total
  count = [200, left].min

  res = fetch_proc.call(count, cursor)
  left -= count
  next_cursor = res.next_cursor

  if (left == 0 || next_cursor == 0)
    return res
  end

  more_res = fetch(left, next_cursor, &fetch_proc)
  more_res.users << res.users
  more_res
end

Answer 1

It looks pretty good to me. Some notes:

• I'd avoid return on the last expression
• I'd avoid the "-=" (not very functional)
• I'd avoid inline returns (write a full-fledged conditional instead)
• I have my doubts about this more_friends.users <<, is this a side-effect you are doing behind the caller's back?

As a general note, Ruby is an OOP language, you can strive for functional style (I do whenever possible), but still, use also an OOP structure or you'll end up with weird undiomatic code.