mcelaney

defmodule VehicleMake do
  schema "vehicle_makes" do
    field :name, :string

    has_many :vehicle_models, VehicleModel
    has_many :vehicles, through: [:vehicle_models, :vehicles]
  end
end

defmodule VehicleModel do

mcelaney

defmodule ProductVehicle do
  def vehicles_that_fit_product(query \\ ProductVehicle, product_id) do
    query
    |> join(:inner,
            [products_vehicles],
            product in assoc(products_vehicles, :product))
    |> join(:inner,
            [products_vehicles],
            vehicle in assoc(products_vehicles, :vehicle))
  end

mcelaney

defmodule ProductVehicle do
  def vehicles_that_fit_product(query \\ ProductVehicle, product_id) do
    query
    |> join(:inner,
            [products_vehicles],
            product in assoc(products_vehicles, :product))
    |> join(:inner,
            [products_vehicles, _product],
            vehicle in assoc(products_vehicles, :vehicle))
  end

mcelaney

defmodule ProductVehicle do
  def vehicles_that_fit_product(query \\ ProductVehicle, product_id) do
    query
    |> join(:inner,
            [products_vehicles],
            product in assoc(products_vehicles, :product))
    |> join(:inner,
            [products_vehicles],
            vehicle in assoc(products_vehicles, :vehicle))
    |> join(:inner,

mcelaney

defmodule ProductVehicle do
  def vehicles_that_fit_product(query \\ ProductVehicle, product_id) do
    query
    |> join(:inner,
            [products_vehicles],
            product in assoc(products_vehicles, :product))
    |> join(:inner,
            [products_vehicles],
            vehicle in assoc(products_vehicles, :vehicle))
    |> join(:inner,

mcelaney

class FizzBuzz
  def self.find_answers_for(max)
    self.new.find_answers_for(max)
  end

  def initialize
    @result = [
      Proc.new do |x| x; end,
      Proc.new do |x| x; end,
      Proc.new do |x| "Fizz"; end,

mcelaney

class FizzBuzz
  def self.find_answers_for(max)
    1.upto(max).each do |n|
      result = ''
      result << 'Fizz' if n % 3 == 0
      result << 'Buzz' if n % 5 == 0
      result = n if result.empty?
      result
    end
  end

mcelaney

class FizzBuzz
  def self.find_answers_for(max)
    self.new.find_answers_for(max)
  end

  def find_answers_for(max)
    1.upto(max).map do |current|
      [find_result_hash(current), current]
        .find { |result| result != '' }
    end

mcelaney

# Run if necessary:
# RubyVM::InstructionSequence.compile_option = {
#   tailcall_optimization: true,
#   trace_instruction: false
# }

class FizzBuzz
  def self.find_answers_for(max)
    self.new(max).find_answers_for([], 1)
  end

mcelaney

defmodule MagicSquare do
  @moduledoc """
  Today's daily programmer challenge is to test a magic square. This challenge
    is stolen verbatim from r/dailyprogrammer. A 3x3 magic square is a 3x3 grid
    of the numbers 1-9 such that each row, column, and major diagonal adds up to
    15. Here's an example:
  ```
  8 1 6
  3 5 7
  4 9 2