Seems the documentation needs to be updated when it comes to using a custom filter module

[acrolink]

After considerable trial and error, these are the correct instructions for this to work:

// patient_filters.ex

defmodule PatientFilters do
  use Filterable.DSL
  use Filterable.Ecto.Helpers
  use Filterable
  import Ecto.Query

  field(:name)
  field(:gender)

  paginateable(per_page: 10)

  filterable do
    @options param: :name
    filter name(query, value) do
      query |> where([u], ilike(u.name, ^"%#{value}%"))
    end

    @options param: :gender
    filter gender(query, value) do
      query |> where(gender: ^value)
    end
  end
end

And in controller:

  def index(conn, _params) do
    with {:ok, query, filter_values} <- PatientFilters.apply_filters(Patient, _params),
         patients <- Repo.all(query),
         do: render(conn, "index.json", patients: patients, meta: filter_values)
  end