Nimster

module Lookup

  module ClassMethods
    #Any new "macros" go here
    def lookup(lookup_name)
    end
  end

  def self.included(host_class)
    host_class.extend(ClassMethods) 

Nimster

class CreateCarTypeLookupForCar < ActiveRecord::Migration
  def self.up
    create_table :car_types do |t|
      t.string :name
      t.timestamps #Btw you can remove these, I don't much like them in type tables anyway
    end

    remove_column :cars, :type #Let's assume you have one of those now…
    add_column :cars, :type, :integer #Maybe put not_null constraints here.
  end

Nimster

    def lookup(as_name)
      mycls = self #Class I'm defined in
 
      #We now define the CarType class, as if we were in a file car_type.rb
      cls = Class.new(ActiveRecord::Base) do #Define a new class, extending AR::Base
        #CarType should have the has_many :cars link
        has_many mycls.name.tableize.to_sym

        #These are optional. You can define any additional constraints you like.
        validates_uniqueness_of :name

Nimster

   def lookup(as_name)
     #...

     #Now, define the foreign key from Car to CarType.
     belongs_to lookup_name.to_s.to_sym, :foreign_key => "#{as_name}".to_sym
     validates "#{as_name.to_s}_id".to_sym, :presence => true

      #Now we define the "delegates" that will allow us to just set call car.car_type = "Sports"
      #Define a setter for car_type
      define_method("#{as_name.to_s}_id=") do |id|

Nimster

    def lookup(as_name)
      #...

      all_vals = cls.all
      cls.class_variable_set(:@@rcaches, all_vals.inject({}) do |r, obj|
          r[obj.name] = obj.id
          r
        end)
      cls.class_variable_set(:@@caches, all_vals.inject([]) do |r, obj|
          r[obj.id] = obj.name

Nimster

# Adapted from http://stackoverflow.com/questions/1686779/multifile-rake-build
# Runs a task (in this case the default task) for each Rakefile nested in the current directory 
task :default do
  FileList["*/**/Rakefile"].each do |project|
    next if project =~ /^admin_console/
    next if project =~ /^logging/
    # clear current tasks
    Rake::Task.clear
    #load tasks from this project
    load project

Nimster

# Often when doing functional style programming you get concerned that copying or
# wrapping objects might cost a lot in terms of performance. But the great thing
# about an immutable object is that I don't need to create a new one if I am
# handed an immutable copy.
# Follow me on twitter @nimrodpriell or see my blog at http://www.educated-guess.com 
# for more bits of knowledge

# This is what we want to figure out the performance of. It is equivalent to calling
# frozenset(frozenset(frozenset(... m times (l)))...))
def frozens(l,m=100):

Nimster

./configure --enable-python27=yes --with-png --enable-ltdl-install --with-included-ltdl --enable-perl=no CC="gcc -arch x86_64" CXX="g++ -arch x86_64"
make
sudo make install

Nimster

collections.defaultdict(lambda: 0) # Hash map with default values

 l = [t for t in l if not t in s] # Given a list l and a set s, returns l without all the elements in s

fun_with_many_args(*[1, 2, 3])  # Splat an array into an argument list

fun_with_named_args(**{'arg1': 1, 'arg2': 2}) # Splat a map (dictionary) for named argument functions!

Nimster

COMMANDS

rails new demo #Create a new rails project under 'demo'

rails server #Start a local server to test the project, port 3000

rails generate controller ControllerName action1 action2 
  # For example 'rails generate controller say hello goodbye' gives
  # say/hello and say/goodbye links, which are implemented by a class 
  # app/controllers/say_controller.rb with hello and goodbye methods.