How to use function in argument of 'operation' macro

[AndriiKlymchuk]

Hello. In order to decrease duplication I want to hide some common part of schema behind function call like that:

  def scrivener_page_schema(entry_schema) do
    %Schema{
      type: :object,
      properties: %{
        entries: %Schema{type: :array, items: entry_schema},
        page_number: %Schema{type: :integer},
        page_size: %Schema{type: :integer},
        total_entries: %Schema{type: :integer},
        total_pages: %Schema{type: :integer}
      }
    }
  end

  operation :index,
    responses: %{
      200 => {"Paginated entries", "application/json", scrivener_page_schema(EntrySchema)},
    }

But I get undefined function scrivener_page_schema/1 error during compilation.

How can I fix my code, or is there any recommended approach how to reduce code duplication in such cases?

[mbuhot]

I think it will work if you move the scrivener_page_schema function to a separate module.

The arguments to the operation macro are unquote, so it will try to invoke the scrivener_page_schema function at compile time before the module has been fully compiled.

https://github.com/open-api-spex/open_api_spex/blob/master/lib/open_api_spex/controller_specs.ex#L208