lukin-io

Originally published in June 2008

When hiring Ruby on Rails programmers, knowing the right questions to ask during an interview was a real challenge for me at first. In 30 minutes or less, it's difficult to get a solid read on a candidate's skill set without looking at code they've previously written. And in the corporate/enterprise world, I often don't have access to their previous work.

To ensure we hired competent ruby developers at my last job, I created a list of 15 ruby questions -- a ruby measuring stick if you will -- to select the cream of the crop that walked through our doors.

What to expect

Candidates will typically give you a range of responses based on their experience and personality. So it's up to you to decide the correctness of their answer.

lukin-io

module Algorithms::Sort
  # Bubble sort: A very naive sort that keeps swapping elements until the container is sorted.
  # Requirements: Needs to be able to compare elements with <=>, and the [] []= methods should
  # be implemented for the container.
  # Time Complexity: О(n^2)
  # Space Complexity: О(n) total, O(1) auxiliary
  # Stable: Yes
  # 
  #   Algorithms::Sort.bubble_sort [5, 4, 3, 1, 2] => [1, 2, 3, 4, 5]
  def self.bubble_sort(container)

lukin-io

module Fr
  module Base
    def self.included(base)
      base.class_eval do
        validate :validate_it
        
      protected
        def validate_it
          return true if something?
        end

lukin-io

• Dynamic Dispatch
• Dynamic Method
• Ghost Methods
• Dynamic Proxies
• Blank Slate
• Kernel Method
• Flattening the Scope (aka Nested Lexical Scopes)
• Context Probe
• Class Eval (not really a 'spell' more just a demonstration of its usage)
• Class Macros

lukin-io

class User
  attr_accessor :name, :pet_name
end

class Factory < BasicObject
  def initialize
    @attributes = {}
  end

  attr_reader :attributes

lukin-io

def fib(n)
  n < 2 ? n : fib(n-1) + fib(n-2)
end  

lukin-io

require 'faraday'
require 'forwardable'

module Soup
  class Agent
    extend Forwardable

    def initialize(domain = 'https://www.soup.io/')
      @agent ||= faraday(domain)
    end

lukin-io

# I was considering how I might want to further implement my gem and incorporate configuration settings for it.  I wanted only one instance of my configuration and it needed to be part of my module.  So I’ve come up with a solution I like that allows me to do this and even have a true “sense” of untouchable constants.

# I’ve found OpenStruct to be for my liking in this situation as it allows for any configuration (variable) to be set on it.  I’ve also found I can set “unalterable” variables… at least through standard assignment options.


# The reason I created the class MyProject::MyConfig just to inherit OpenStruct is that I want my configuration to be identified by a class name that indicates it is a config object that belongs to my project.  In module MyProject I use attr_reader for config because we are getting the OpenStruct instance handed back to us and we can still invoke method/value assignment on it.  I use the single class variable @config for the internal singleton value because it’s not going a

lukin-io

my_hash.inject({}){|memo,(k,v)| memo[k.to_sym] = v; memo}

lukin-io

source 'https://rubygems.org'

gem 'rake'
gem 'lotus-router'
gem 'lotus-controller'
gem 'lotus-view'

group :test do
  gem 'rspec'
  gem 'capybara'