I’m working on a cool library (news about that in a few weeks :smiley:), and there’s no sugar coating this: I really want to use inheritance. I’m no Elixir n00b, at least not completely. I’ve enjoyed the functional paradigm shift very much, but in this particular case, I can’t help but feel like I’…

hehe nice! That’s it. Inheritance solved! Now it looks like this defmodule MyConfig do @callback attr_value(atom(), atom()) :: atom() @optional_callbacks attr_value: 2 end defmodule BaseBaseConfig do @behaviour MyConfig def attr_value(:category, :name), do: :base_base_name def attr_…

I presume you mean something more advanced than a module attribute? defmodule ChildConfig do @behaviour MyConfig @delegate BaseConfig def attr_value(:category, :name), do: :child_name defdelegate attr_value(a, b), to: @delegate end

Oh man, thanks this is awesome. I got lost in a sea of macros when the solution was so simple :slight_smile: Thanks!

First, do not use Config as the name for your behaviour since it is a module in Elixir. Then I would work with module attributes and do compile time checks. What i usually do is create functions in the behaviour module that are called by default with the default implementations defined in __using_…

This is what I’ve implemented numerous times and works well. Something similar is shown in the article Macro Madness: How to use `use` well - DockYard .

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Inheritance in Elixir

Questions & Help Questions

dimitarvp September 5, 2023, 1:51am 2

Quick shot at this: why not use defdelegate in the derived (child) configs?