Has anyone seen Building Tetris on Elixir/LiveView?

I like the game and saw yesterday a little.
I will buy this month for sure it’s a nice price.

Does anyone have any comments about the teaching approach to LiveView specifically, and Elixir in general? Basically, my approach is to get students to reducers, and using them in the context of an API. Once I can get them there, it gets easier.

Comments?

Are reducers the functionally pure way to interact with your data structure (like a brick or board)? I’m only on the second video but I plan on watching these soon. I’m happy to give more specific feedback once I’m the whole way through it.

If yes, I think that’s pretty sound. It’s much easier to think about the problem in bite size chunks rather than tackling it all at once. I think that learning to decompose the problem (what are the reducers and functional core of my app going to be?) is one of the most important—but also subtly difficult—parts of learning to write good applications.

yep… it’s a little cloudy in Elixir because Enum.reduce takes an accumulator as the SECOND argument, but we tend to build modules with the target item as the FIRST argument. So… we’re looking at something like:

brick
|> rotate(90)
|> right
|> down

to move the conceptual model of the brick. At another level, we use a points module. Not a struct, but applies to functions we’re using to manipulate a list of points:

def rotate(points, 90) do
  points 
  |> transform #{x, y} to {y, x}
  |> mirror
end
def rotate(points, 0), do: points
def rotate(points, degrees) do
  rotate(
    rotate(points, 90), 
    degrees - 90
  )
end

rotate on points is a reducer.
On brick: rotate, right, left, down are all reducers.

-bt

This looks really nice and was exactly the sort of thing I was hoping you’d do Bruce!

I think I am going to go through it after the Phoenix book

Just a couple of quick questions…

• Is the $10 for the complete course (or is it $10 per video)
• Is there a time limit on that offer? (Should we buy now or is it ok to wait a little while?)
• Is there a time limit on access to the course once you’ve bought it?

Finally, do you want us to move this thread to the #courses section? People (especially newcomers) are more likely to browse those sections. If so let me know and we’ll make some edits and move it there

$10 for all of them

Basically, I had to make them for the mentoring program as there’s one of me and four groups, and someone came up with the idea of selling them to support the program.

-bt

Just finished the course, easy to follow and I learned a bunch while building the app. Highly recommended if you are already mid-level-ish in the language. And it’s a good introduction to LiveView.

I’m a newbie in this language. And I think it’s a good starter.
I’m on ep 3 for now.

Do you mean by “reducers” functions that takes and returns Ecto.Changesets and Plug.Conns (and the like) that typically always return the same data structure as its first parameter?

I mean this applies if I consider a reducers as functions that take two parameters and apply (or use) the second parameter in order to return a transformed version (or not) of the first parameter (like Redux in front-ends with DOM States and events..)

As an Elixir beginner (coming from Ruby), it took me some efforts to grasp the fact that those kind of functions works well with data structure that have both inputs and outputs (like Plugs.Conn, or Ecto.Changeset) and it seems that this is a big “pattern” in FP and used almost everywhere.

So, I think (at least for me) that this is indeed something really important to teach/learn particularly for custom data structures (in contrast to Plugs, and Changesets, where we simply use them rather to design them..)

So I hope I will learn a lot from these videos..

Edit: I just realized that you are Bruce Tate.. Thank you for the videos BTW..

Hello @redrapids,
To answer to the question of the topic, now I took the course..
Well.. I’m kinda left hungry for more, particularly regarding the “LiveView” parts..
I mean, the course name is “Phoenix Liveview Tetris in Elixir” but it happens to me as if it was “Tetris in Elixir”.

I learn more about Liveview in this video of you https://www.youtube.com/watch?v=-wzabRyc-0M (saw on the forum) and even more in this one from Chris McCord https://www.youtube.com/watch?v=8xJzHq8ru0M

For example, I expected to see more about the mechanisms that allow to start from the custom attribute written in the HTML part of Phoenix all the way down to the Elixir part where the events are handled.

Also a better explanation of the whole flow (including the JS parts) and all the life cycles (from the first HTTP request, to the mount of the WebSocket, and the rest) would be really appreciated.

Even if there is no need to write JS with LiveView, there is still some JS involved, it would have been also great if those default JS parts included by Phoenix were a little explained particularly how LiveView is different from regular WebSockets.

I also expected to learn more about the events and the whole process (including morphdom) as it’s a little explained by Chris on his video.

In that video above (where LiveView was quite new at that moment) you explained, that many events are handled by Phoenix but it’s even easier to add custom events.. So I would have expected this part to be present in the course too.

But maybe it’s me and there is no need to talk more about LiveView, I don’t know…

Anyway, it was not that expensive at least, so no regret for me…

And by the way, many thanks for all the effort put into all these learning resources..