Looks great.

Perhaps we should go a step further and replace the first example with the one you've prepared for the last example (i.e. adding a corresponding nested ifversion)?

Yeah that might be a good idea. We are looking at it now as well, this if example is also what is used to introduce if, but it's not a very good example. Something that's unrelated to the turtle thing would also be better there.

👍

Looks good to me!

Hold off on it a little longer, I'm making more changes to the control flow chapter to remove references to the turtle thing

What about starting with: (ordinal 1) and (ordinal 2), then progressing to 3+ rather than skipping 2nd/3rd?

I thought it made more sense this way because "th" is the general case (the :else case).

Yeah I know what you mean.

At that point though, they've not seen :else so they will still be thinking in pair-wise splits (i.e. not specifics vs general). It just seemed more natural to me to handle them in order.

I don't suppose it'll make much difference either way.

Yeah I can see your point as well, it might help to drive home the point that the "else" branch is not equivalent to the "if" branch though, since it's really more of a catch-all/fallback.

Many people won't be familiar with the word "ordinal". It's introduced straight away with some examples so it should be reasonably clear from context, and the coach can clarify. Would that be good enough, or should we add an extra paragraph to introduce the "ordinal" concept?

The second version of ordinal is actually still not 100% correct, e.g. 21st, 102nd. Maybe best to remain silent about that, or do we add that generalisation as a bonus exercise as well?

I think ordinal is easy enough to explain - you might add a "Details" link though. It's not as mathsy as modulo etc.

Dealing with 102nd etc is a good exercise but that will require people to use modulo! At least that's how I'd solve it..?

You would need modulo, yeah, and an exception for 11th, 12th, 13th. This how Ruby on Rails implements it

def ordinal(number)
  abs_number = number.to_i.abs

  if (11..13).include?(abs_number % 100)
    "th"
  else
    case abs_number % 10
      when 1; "st"
      when 2; "nd"
      when 3; "rd"
      else    "th"
    end
  end
end

I would rather not point that out though, I don't think people should go that deep on this one exercise.

Ah yeah. Good point. Maybe that's better swept under the carpet for now!