Dry

Dry tries to provide a nice DSL for building complex data structures, without having to do custom mappings and validation. It's highly inspired by Ruby's dry-struct library.

Usage

defmodule Sibling do
  use Dry

  alias Dry.Types

  schema do
    attribute(:name, Types.String)
  end
end

defmodule User do
  use Dry

  alias Dry.Types

  schema do
    attribute(:name, Types.String)
    attribute(:age, Types.Integer.options(optional: true))
    attribute(:height)
    attribute(:brother, Sibling.options(optional: true))
    attribute(:sister, Sibling.options(default: %Sibling{name: "Karen"}))
    attribute(:country, Types.String.options(default: "UK"))
    attribute(:siblings, Types.Array.options(type: Sibling))
    attribute(:favourite_colours, Types.Array.options(type: Types.String, default: ["blue", "green"]))

    attribute :is_adult do
      Map.get(entity, :age, 0) >= 18
    end

    attribute :tall do
      Map.get(entity, :height, 0) >= 180
    end
  end
end

user = User.new!(name: "Rob", age: 18, height: 169, country: "BG", siblings: [%{name: "John"}])
user == %User{
  age: 18,
  country: "BG",
  height: 169,
  is_adult: true,
  name: "Rob",
  brother: nil,
  sister: %Sibling{name: "Karen"},
  tall: false,
  siblings: [%Sibling{name: "John"}],
  favourite_colours: ["blue", "green"]
}
{:ok, _user} = User.new(%{name: "Rob", age: 18, height: 169, country: "BG", siblings: [%{name: "John"}]})  ```

Installation

If available in Hex, the package can be installed by adding dry to your list of dependencies in mix.exs:

def deps do
  [
    {:dry,  0.1.2"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/dry.