Allows mapping subject structure into one or more distinct subject records to denote that any of these must be authorized to perform an action.

Default mapping (implementation for Any) returns [subject] for a given subject, so all permissions will be checked against a single subject structure.

Example - scenario of a multi-user session, in which any signed-in user must have permissions for authorization to be granted:

defmodule User, do: defstruct id: 1, name: "foo", role:
defmodule UserSession,
  do: defstruct session_id: 1, current_users: []

defimpl Permit.SubjectMapping, for: UserSession do
  def subjects(%UserSession{current_users: current_users}) do
    current_users
  end
end

defmodule Permissions do
  use Permit.Ecto.Permissions, actions_module: Permit.Actions.CrudActions

  def can(%User{role: :reader} = user), do: permit()
  def can(%User{role: :auditor} = user), do: permit()
end

defmodule Authorization, do: use Permit, permissions_module: Permissions

iex(1)> Authorization.can(%UserSession{users: [%User{role: :reader}, %User{role: :auditor}]}) iex(2)> |> Authorization.update?(%Article{}) true