r00k

My favorite composition vs. inheritance metaphor:

There are only two types of relationships in an object model: composition and inheritance. Both have analogs in a family tree. A composition relation is like a marriage between objects. It is dynamic, it happens during the participating objects' lifetimes, and it can change. Objects can discard partners and get new partners to collaborate with. Inheritance relations are more like births into the family. Once it happens, it is forever. Just as both marriage and ancestry appear in the same family tree, composition and inheritance coexist in a single object model.

(from Object Design - Roles, Responsibilities and Collaborations)

r00k

# This works, right now:

class EmailCaptureCampaign < ActiveRecord::Base
  has_many :campaign_merchants, :as => :campaignable, :dependent => :destroy
  has_many :merchants, :through => :campaign_merchants
end

class Merchant < ActiveRecord::Base
  has_many :campaign_merchants, :dependent => :destroy
  has_many :campaigns, :through => :campaign_merchants, :source => :campaignable, :source_type => 'EmailCaptureCampaign'

r00k

class HumanizedTagContext
  def initialize(game, context)
    @game     = game
    @context  = context
  end


  def to_s
    case @context
      when "location"

r00k

Dependency Injection

Pros

• Classes are more modular, as they depend only on the interface of passed-in dependencies. Class behavior can be changed by swapping out a new component.
• Testing is simplified, since stubs can be substituted for any dependency.

Cons

• It's harder to understand how a class works when reading just that class. You may have to track down its invocation to see what kind of components are passed in.

r00k

class User
  def charge_for_subscription
    PaymentActions.new(user, BraintreeGemSomethingSomething.new).charge_for_subscription
  end
end

class PaymentActions
  def initialize(user, braintree)
    @user, @braintree = user, braintree
  end

r00k

hardstatus alwayslastline "%{= KW}%-w%{= ck}%50>%n %t%{-}%+w%<%-22=%{w}%c [%l]"

nonblock 5

# detach the screen if we get disconnected
autodetach on

# Show messages at the bottom for only 0.5s
msgwait 0.5

r00k

[Ben Orenstein]

Contact details

• Email: [email protected]
• Twitter: @r00k
• Company: thoughtbot

Speaker bio

r00k

class ClaimApplier
  def initialize(order, claims)
    @order = order
    @claims = claims
  end

  def apply
    @claims.sort_by(&:expires_at).each do |claim|
      apply_claim(claim)
    end

r00k

function! OpenJasmineSpecInBrowser()
  let filename = expand('%')
  let url_fragment = substitute(filename, "spec/javascripts", "evergreen/run", "") 
  let host_fragment = "http://localhost:3000/"
  let url = host_fragment . url_fragment
  silent exec "!open ~/bin/chrome" url 
endfunction

r00k

subscription_ids_of_users_billed_next_month = ["2znd7r", "4cm6x6", "4pjyn6", "5sjmhr", "bk8bpb", "3hfmx6", "48k4jw", "57ffpw", "7f8yyb", "9fs8n6", "54vsh6", "5kk2x6", "6b28jw", "gtvm8w", "8fqqjb", "g7kydb", "3zv28w", "7mpvpw", "fzms8b", "2vzhnr", "cdyyb2", "54v2m2", "cxwx62", "km59g2", "2zg5xr", "3p7m4b", "6s7q2m", "76b6m2", "85mg4b", "94wqmm", "9ndr4b", "9tj2hr", "c2ncwm", "cdvyqg", "dd687r", "f82ysr", "fsdw22", "h6bk2m", "hcrt7r", "hjw4n6", "j5xsbm", "k8nks6", "kfrw6m", "3w9y36", "dw2c62", "gfrctb", "k4t4gm", "jmb976", "b5pyn6", "j5j26m", "9yb222", "j52dsr"]
subscription_ids_of_users_billed_this_month = ["5brqxr", "j25stb", "jng6m2", "2hw8w2", "bcbzs6", "5kmjqg", "87f762", "cgxwx6", "dg86fg", "fypcyw", "hztk76", "jwk6hr", "jzyqg2", "kmp7dw", "dx7xkg", "hvcx8b", "bvqp7r", "567gtw", "5xyhkg", "bbj8db", "hw6ygm", "4v77bm", "jc76pb", "24bqmm", "7nkhbm", "9vf2m2", "jk3d7r"]

next_month_users = User.all.select { |u| subscription_ids_of_users_billed_next_month.include?(u.braintree_subscription_token) }
this_month_