ruby operator precedence explained with an example

OR has lower precence than ||, in particular assignments (=) are in the middle, therefor:

a = false || true # => true
a                 # => **true**  => a = (false || true)
# BUT
a = false or true # => true
a                 # => **false** => (a = false) or true

# another BIG difference
:a || :b && :c  # => :a          => (:a || :b) && :c
# BUT 
:a or :b and :c # => **c**       => :a or (:b and :c)

Got it?
Where does it make sense to use the English operators?

a = value or raise "a cannot be nil"

def tail_color(args)
  animal = args[:animal] and
  tail = animal.tail and
  tail.color
end

Conclusion: only use English operators for flow control, not in if statements
also see this table

Ruby, Rails and Etc conventions

• ruby
• rails (includes rspec)
• rails code struture in models consistent
• my gist for conventions

validates exclusion of controller names when catching all routes

Of course catching all routes is bad, but if you have to:

class Account < ActiveRecord::Base
  INVALID_PAGE_NAMES = Dir[Rails.root.join('app/controllers/*_controller.rb')].map { |path| path.match(/(\w+)_controller.rb/); $1 }
  validates :page_name, :exclusion => { :in => INVALID_PAGE_NAMES,
    :message => "Page %{value} is reserved." }
end

rials and ruby postcasts and screencasts

• Ruby5 Podcast
• Ruby Show
• RoR Podcast
• http://www.sdruby.org/podcast
• http://rubyshow.com/
• ruby tapas (screencasts)
• codeschool TV 

Also worth checking

• the changelog

rspec, capybara and factorygirl hints

# spec_helper.rb

# this line will make rpsec end at the first failing test
RSpec.configure do |c|
  c.fail_fast = true
end

# in integration specs

# xpath can be copied from chrome, rx-click on the element (in the dev-tool)
page.should have_xpath("//a[contains(@href,'users')]"), count: num)

rails sandbox tasks

desc 'do not permanently write on the db (good for testing rake tasks)'
task :sandbox => :environment do
  puts "** << USING SANDBOX!! >> **"

  # beginning
  ActiveRecord::Base.connection.increment_open_transactions
  ActiveRecord::Base.connection.begin_db_transaction

  # end
  at_exit do
     ActiveRecord::Base.connection.rollback_db_transaction
     ActiveRecord::Base.connection.decrement_open_transactions
  end    
end

yaml defaults example (postgres on ruby on rails)

postgres:   &postgres
  adapter:  postgresql
  encoding: unicode
  host:     localhost
  username: netengine
  password:

development:
  <<: *postgres
  database: propertyconnect_development

test:
  <<: *postgres
  database: propertyconnect_test