ZoiDefstruct - an extension for Zoi to generate Elixir struct

[wingyplus]

I just did a dirty hack after seeing Zoi on x.com a few hours ago.

Quick Introduction

The zoi_defstruct is a library to help you generate a struct from the Zoi object schema (over Zoi.object). Let’s see a small example below:

defmodule K8S.Deployment do
  use ZoiDefstruct

  @schema Zoi.object(%{
            apiVersion: Zoi.string(),
            metadata:
              Zoi.object(%{
                name: Zoi.string()
              }),
            spec:
              Zoi.object(%{
                replicas: Zoi.integer() |> Zoi.optional()
              })
          })

  defstructure(@schema)
end

When you call a defstructure The macro generates a struct with enforced keys and typespec for you automatically. So in the IEx, you can see:

A struct:

iex(4)> K8S.Deployment.__struct__()
%K8S.Deployment{spec: nil, metadata: nil, apiVersion: nil}

A typespec declaration:

iex(1)> t K8S.Deployment
@type t() :: %{
        spec: %{optional(:replicas) => integer()},
        metadata: %{name: binary()},
        apiVersion: binary()
      } 

ArgumentError if it has no required keys:

iex(5)> %K8S.Deployment{}
** (ArgumentError) the following keys must also be given when building struct K8S.Depl
oyment: [:spec, :metadata, :apiVersion]
    (examples 0.1.0) expanding struct: K8S.Deployment.__struct__/1
    iex:5: (file)

Since this is a quick hack, it has numerous edge cases that need to be addressed. Please feel free to provide feedback or suggestions. Opening an issue or pull request is very welcome.

I need to give special thanks to Zoi for making this awesome library!

GitHub - wingyplus/zoi_defstruct: Let's define a struct from Zoi

[byu]

Great. will check it out.

How does it differ from zoi/lib/zoi/struct.ex at main · phcurado/zoi · GitHub ?

[phcurado]

awesome @wingyplus

You can leverage some of the helpers on the Zoi Struct module as @byu mentioned. I personally decided to not add any macros into the library (unless strictly necessary like infering type specs) but I added these helpers for anyone who wishes to extend it.
Thanks for using Zoi, awesome to see this

[wingyplus]

Thanks for the comment

Actually, it’s a wrapper of those three functions to avoid repetition works.

[wingyplus]

Thanks for the comment.

I just see that Zoi has a struct helper already (from @byu mentioned). Will refactoring to use those functions instead.

[nulltree]

I’m so happy libraries like Zoi seem to catch on and inspire extension (infant adoption steps, but still).

They complement my way of thinking really well!

[wingyplus]

Update from the latest main. The defstructure is now changed to defstruct and you can embed the schema into defstruct directly.

The API also use Zoi.Struct under the hood. So the enforce keys and struct declaration is now align with the Zoi upstream.

[wingyplus]

Type composition is now working! You can use t() function to reference another struct.

[wingyplus]

The library is now published on Hex zoi_defstruct | Hex . Feel free to provide feedback, open issues, or pull requests.