compile_function() ::
  ({name :: String.t(), code :: binary(), module(), nil | module()} ->
     :ok | {:error, term()})

formula_def() :: {module(), formula_name(), context :: module()}

formula_full_def() :: formula_def() | {module(), name :: String.t()}

formula_name() :: String.t()

t() :: %Formular.Client.Config{
  client_name: String.t(),
  compiler: {module(), atom(), args :: list()} | compile_function(),
  formulas: [formula_def()],
  url: String.t()
}