Refine Take-A-Number

[angelikatyborska]

Resolves #1482

This PR reverts #1486 - see my new comment in that PR to know why.

This PR re-distributes work between step 1 and step 2. Previously, step 1 assumed you would already start the receive loop. That doesn't make sense because there is no unit test for step 1 that could test that you have done this correctly. So I'm moving that to step 2.

[github-actions]

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---

Automated comment created by PR Commenter 🤖.

[angelikatyborska]

I hope those instructions are explicit enough to lead people to a solution similar to the exemplar

[jiegillet]

I think they should be

[angelikatyborska]

I hope that the phrase "receive loop" will remind people of the paragraph with the same title from the introductions

[jiegillet]

Have you considered adding some example code in the receive loop section? I think code will make it a lot more memorable. Something like:

def loop(ping_count) do
  receive do
    {:ping, sender_pid} ->
      send(sender_pid, :pong)
      loop(ping_count + 1)
  end
end

It's pretty close to the solution though.

[angelikatyborska]

Yes, many times, but it is clearly against the recommendation:

Code examples should only be used to introduce new syntax (students should not need to search the web for examples of syntax). In other cases provide descriptions or links instead of code.

Defining a recursive function is not new syntax...

[angelikatyborska]

Are those comments helpful? I was staring at this snippet and I was afraid that people might not understand that this code is an example code of how to test the implementation of the machine, and not the code that should go into the implementation of the machine 🤔

[jiegillet]

I see your concern, but that's usually what those code snippets do.
Maybe if you wanted to be even more explicit, you could frame those as tests?

  test "reports its own state" do
    pid = TakeANumber.start()
    send(pid, {:report_state, self()})
    assert_receive 0
  end

but that might not help so much.
I think adding the comments is fine for now.

[jiegillet]

It looks like a nice improvement.
Sorry I didn't look too closely at #1486.

[jiegillet]

Have you considered adding some example code in the receive loop section? I think code will make it a lot more memorable. Something like:

def loop(ping_count) do
  receive do
    {:ping, sender_pid} ->
      send(sender_pid, :pong)
      loop(ping_count + 1)
  end
end

It's pretty close to the solution though.

[jiegillet]

I see your concern, but that's usually what those code snippets do.
Maybe if you wanted to be even more explicit, you could frame those as tests?

  test "reports its own state" do
    pid = TakeANumber.start()
    send(pid, {:report_state, self()})
    assert_receive 0
  end

but that might not help so much.
I think adding the comments is fine for now.

[jiegillet]

I think they should be