jeffnv

Ways to Call a Function

Let's review the various ways to call a function that we have encountered:

• Function-style when unbound (fun(arg1, arg2))
  • this is set to the global context (global or window)
• Method-style (obj.method(arg1, arg2))
  • this is set to obj
• Constructor-style (new ClassName(arg1, arg2)).
  • Creates a new, blank object.

jeffnv

class ARBase
  def self.already_built_attr_methods?
    @already_built_attr_methods
  end

  def method_missing name, *args
    unless self.class.already_built_attr_methods?
      self.class.build_attr_methods
      #try it again
      self.send(name, *args)

jeffnv

class Gist < ActiveRecord::Base
  attr_accessible :title, :user_id, :gist_files_attributes, :tags_attributes
  belongs_to :user
  has_many :favorites
  has_many :gist_files
  has_many :taggings
  has_many :tags, through: :taggings, source: :tag
  accepts_nested_attributes_for :gist_files, :tags
end

jeffnv

def create
  current_user.friend_ids = params[:friend_ids]
  current_user.save
  redirect_to friend_circles_url
end

jeffnv

def create
  @user = User.find_by_credentials(params[:user][:user_name],                                                      params[:user][:password])

  if @user.nil?
    flash[:errors] = ["Credentials were wrong"]
    render :new
  else
    self.current_user = @user
    redirect_to cats_url
  end

jeffnv

def self.contacts_for_user_id(user_id)
  c = Contact.joins(<<-SQL)
  LEFT JOIN contact_shares cs ON cs.contact_id = contacts.id
  SQL
  c.where("contacts.user_id = ? OR cs.user_id = ?" , user_id, user_id)
end

jeffnv

def has_many(name, params = {})
  hsp = HasManyAssocParams.new(name, params, self.class)
  assoc_params[name] = hsp
  define_method(name.to_sym) do 
    sql = <<-SQL
    SELECT *
    FROM #{hsp.other_table} other
    WHERE other.#{hsp.params[:foreign_key]}  = ?
    SQL
    many = DBConnection.execute(sql, self.id)

jeffnv

def results
    responses = Question.joins(<<-SQL)
      LEFT OUTER JOIN answer_choices
      ON answer_choices.question_id = questions.id
      LEFT OUTER JOIN responses
      ON answer_choices.id = responses.answer_choice_id
    SQL
    responses = responses.where("questions.id = ?", self.id)
    p responses
    responses.group('answer_choices.answer_body').count('responses.id') 

jeffnv

def avg_karma
    results = QuestionsDatabase.instance.execute(<<-SQL, @id, @id)
    SELECT (COUNT(questions.id) *1.0/ (SELECT COUNT(*) FROM questions WHERE user_id = ?))
    FROM questions JOIN question_likes ON (question_likes.question_id = questions.id)
    WHERE questions.user_id = ?
    SQL
    results[0].values[0]
end

jeffnv

SELECT a.company, a.num, a.stop, b.stop
FROM route a JOIN route b ON
  (a.company=b.company AND a.num=b.num)
WHERE a.stop=53