I have a form with arbitrary levels of deeply nested associations. One particular association that lives a couple of levels down can have an upload associated with it. To track these I need to allow_upload based on the indices of each level. Currently this looks like this: socket.assigns.form.so…

It’s a great tool, one of the main reasons I like Elixir. Yes, if you need to update the socket, then you can tack on reduce: assoc_with_index = fn changeset, assoc -> changeset |> Ecto.Changeset.get_assoc(assoc) |> Enum.with_index() end source = socket.assigns.form.source for {mockup, moc…

When you start dealing with nested iterative structures, for is your best bet. assoc_with_index = fn changeset, assoc -> changeset |> Ecto.Changeset.get_assoc(assoc) |> Enum.with_index() end source = socket.assigns.form.source for {mockup, mockup_index} <- assoc_with_index.(source, :mockups…

[image] 100phlecs: for is your best bet. It also supports reduce, to allow wiring the socket state through.

Beautiful! So much nicer than what I was thinking. Thank you both!

This brings me joy! The for comprehension is so nice.

I would also consider an approach where I would break this down into small functions, so the main function eould be flat.

I would do that if this became a common pattern. As it stands this is the only place in the app where I’m needing to index associations in order to enable uploads and this logic is already inside a private function, so I don’t want to break things up too much. Part of me actually still prefers my …

FWIW the for variant, while shorter, is absolutely opaque and is making it pretty hard to mentally parse and understand what is going on. I see nothing wrong with your original function but if you really have to act I would either (a) add a Credo exception or (b) make two sub-functions – correspond…

Ya, I might revert to my original version and completely kill the Credo rule as indenting too deeply isn’t something that happens often (I’m ok with outright removal of linting rules). The more I think about it, it’s really a pretty useless rule unless you are working with an army of developers you…

[image] sodapopcan: I do actually always use for whenever I need a Cartesian product of two collections but for some reason as soon as I needed the product of three I was like, “duhhhhhhhhhhh what do I do better ask the internet!”. I agree that for can be slightly “prettier” than a chain of E…

[image] dimitarvp: Obviously go for the variant that makes it least likely to hate yourself when you revisit this code in the future. Yep, basically this. Working solo has actually given me the luxury to carve out some time to go back and re-read stuff I wrote a week ago and see how quickly …

Help me rewrite these nested reductions?

Questions & Help Questions

LostKobrakai July 12, 2023, 4:26pm 3

It also supports reduce, to allow wiring the socket state through.