Thanks for pointing out the confusion with the example.
Domo brings several possible benefits. And more explicit version of the example can be like this:
mix new try_domo && cd try_domo && asdf local elixir master
sed -i '' 's/# {:dep_from_hexpm, "~> 0.3.0"}/{:domo, ">= 0.0.0"}/g' ./mix.exs
echo """
defmodule Order do
use Domo
deftag Id, for_type: String.t()
typedstruct do
field :id, Id.t()
field :note, :none | String.t(), default: :none
field :quantity, integer
end
end
""" > lib/order.ex
echo """
defmodule User do
use Domo
deftag Id, for_type: String.t()
typedstruct do
field :id, Id.t()
field :name, String.t()
end
end
""" > lib/user.ex
mix deps.get && iex -S mix
iex(1)> import Domo
iex(2)> alias Order.Id
iex(3)> Order.new!(
...(3)> id: Id --- "156",
...(3)> quantity: 150
...(3)> )
%Order{
id: {Order.Id, "156"},
note: :none,
quantity: 150
}
iex(4)> Order.new!(
...(4)> id: Id --- "157",
...(4)> note: "Clear out the delivery date",
...(4)> quantity: 220
...(4)> )
%Order{
id: {Order.Id, "157"},
note: "Clear out the delivery date",
quantity: 220
}
iex(5)> Order.new!(
...(5)> id: User.Id --- "157",
...(5)> quantity: 540
...(5)> )
** (ArgumentError) Can't construct %Order{...} with new!([id: {User.Id, "157"}, quantity: 540])
Unexpected value type for the field :id. The value {User.Id, "157"} doesn't match the Id.t() type.
(try_domo 0.1.0) lib/domo/struct_functions_generator.ex:20: Order.new!/1
(stdlib 3.11.1) erl_eval.erl:680: :erl_eval.do_apply/6
(iex 1.11.0-dev) lib/iex/evaluator.ex:258: IEx.Evaluator.handle_eval/5
iex(6)> Order.new!(
...(6)> id: "156",
...(6)> note: nil,
...(6)> quantity: "One hundred fifty"
...(6)> )
** (ArgumentError) Can't construct %Order{...} with new!([id: "156", note: nil, quantity: "One hundred fifty"])
Unexpected value type for the field :id. The value "156" doesn't match the Id.t() type.
Unexpected value type for the field :note. The value nil doesn't match the :none | String.t() type.
Unexpected value type for the field :quantity. The value "One hundred fifty" doesn't match the integer type.
(try_domo 0.1.0) lib/domo/struct_functions_generator.ex:20: Order.new!/1
(stdlib 3.11.1) erl_eval.erl:680: :erl_eval.do_apply/6
(iex 1.11.0-dev) lib/iex/evaluator.ex:258: IEx.Evaluator.handle_eval/5