ROM - References for creating a custom adapter

rom-references

require 'rom'

ROM.setup(:memory)

class User
  attr_reader :name, :age

  def initialize(attributes)
    @name, @age = attributes.values_at(:name, :age)
  end
end

class Users < ROM::Relation[:memory]
  def by_name(name)
    restrict(name: name)
  end

  def adults
    restrict { |user| user[:age] >= 18 }
  end
end

class UserMapper < ROM::Mapper
  relation :users
  register_as :entity

  model User

  attribute :name
  attribute :age
end

class CreateUser < ROM::Commands::Create[:memory]
  register_as :create
  relation :users
  result :one
end

class UpdateUser < ROM::Commands::Update[:memory]
  register_as :update
  relation :users
  result :one
end

rom = ROM.finalize.env

user1 = rom.command(:users).as(:entity).create.call(name: "Joe", age: 17)
user2 = rom.command(:users).as(:entity).update.set(name: "Jane", age: 18)
puts user1.class, user2.class # => User, Hash

Q: "What's a repository?"

A: ""Repository" is poorly named, as it doesn't actually reflect a repository pattern
the Adapter's repository is the class it uses to interact with whatever it's backend is
more of a gateway
thus, each adapter has 1 repository
but, what you register is an instance of an adapter
which in turn ends up with an instance of it's internal repository class"