kleisli-inspired spike for handling inserts with associations in rom-rb

try_spec.rb

class Result
  attr_reader :value, :error

  class Success < Result
    def initialize(value)
      @value = value
    end

    def >(f)
      f.call(value)
    end
  end

  class Failure < Result
    def initialize(error)
      @error = error
    end

    def >(&f)
      self
    end
  end
end

def try(&f)
  Result::Success.new(f.call)
rescue => e
  Result::Failure.new(e)
end

describe 'try' do

  it 'somehow works' do
    input = { name: 'Piotr', tasks: [ { title: 'First' }, { title: 'Second' } ] }

    insert_user = Proc.new do |user|
      user.merge(id: 1)
    end

    insert_task = Proc.new do |task, user|
      task.merge(user_id: user.fetch(:id))
    end

    insert_tasks = Proc.new do |tasks, user|
      tasks.map { |task| insert_task[task, user] }
    end.curry[input[:tasks]]

    result = try {
      insert_user[input]
    } >-> user {
      try {
        insert_tasks[user]
      }
    }

    expect(result.value).to eql(
      [{ user_id: 1, title: 'First' }, { user_id: 1, title: 'Second' }]
    )
  end

end

oh my

😱 I know ;)