Mix and OTP guide, part 6: Need to update KV.Supervisor sooner about elixir-lang.github.com

[josevalim]

You are right!

It is not supposed to matter though because the supervisor is meant to pass three arguments. In the last section of chapter 5 we have:

worker(KV.Registry, [@manager_name, @bucket_sup_name, [name: @registry_name]])

We are passing the wrong arguments but it doesn't matter because we are not accessing that application yet in tests.

So there is a bug but you were not supposed to see it. :) I will leave this open because you are the second person to comment on this, which means it is time to improve it.

[ccblaisdell]

Aha, I suspected I was doing something wrong :) I definitely missed adding @bucket_sup_name into the worker call.

I've made errors like this several times while following this guide. In fact, I got so stuck on my first run through that I scrapped it and started over. Is it possible with Github to highlight the changed sections with a different color or background (for example), in addition to the comments? I find it difficult sometimes to see some of the changes when looking back and forth between the guide and my editor.

[josevalim]

@ccblaisdell I don't think we can highlight but I guess we could mark the sections that were change using comments?

## Changed the supervisor arguments

and so on?

[ccblaisdell]

That would help me immensely. I know there's already plenty of that going on in the guide already, but even more documentation would be great.

[dbbrian]

I'm probably not the first one to come up with it, but I have a (terrible) hack for that... Markdown allows HTML, and comments are valid HTML, so with something like this in the .markdown file:

<!-- data-emphasize-lines: 2, 4 -->
```elixir
defmodule Math do
  def sum(a, b) do
    a + b
  end
end

And a few lines of JS and CSS, make this:

Looks like this:

I may have used that kind of trick in prod. to embed some Google Maps things... 😁

[sircharleswatson]

@dbbrian That's a good idea and I think it'd make things much clearer. is there any way to specify a different color maybe?

[dbbrian]

@sircharleswatson Thanks! And sure, the CSS can be tweaked, or the code could be extended to support multiple data- attributes.

Or something really dirty like this:

<!-- data-emphasize-lines: 2#123456, 4#abcdef -->
```elixir
defmodule Math do
  def sum(a, b) do
    a + b
  end
end

It's just an hacky way to get metadata to the client, once you have it you can parse it, and use it however you need.

/cc @josevalim