Lessons learned from Heroku Waza Conference 2013. Particularly Matz's talk on Ruby 2.0

1. Heroku waza 2013
Lessons Learned
Pete Hudgins
Twitter: @phudgins
Github: phudgins

2. Waza?
Art, Technique

3. I attended
•Keynote - Michael Lopp
•Unfactoring - Aaron Patterson
•Dismantling the Monorail - Jack Lawson
•Design Minded Development - Austin Bales
•Instrumenting Twelve-Factor Apps - Joseph Ruscio
•Caring for your Baby Ecosystem - Jacob Kaplan-Moss
•Ruby 2.0 - Yukihiro 'Matz' Matsumoto
•Everything is a Remix - Kirby Ferguson

4. Ruby 2.0

5. Yukihiro 'Matz'
Matsumoto
@yukihiro_matz
• Creator of Ruby
• Hired by Heroku as ‘Chief
Architect, Ruby’

6. Why Ruby?
"I hope to see Ruby help every programmer in the world to
be productive, and to enjoy programming, and to be happy."

8. Ruby 2.0
“Happiest release ever"

9. Why Ruby 2.0?
• 1.8.7 will die SOON
• ‘100% Compatible’ with Rails 4.0
• Available on Heroku NOW
• Cool new features

10. Ruby 2.0 Features
• Keyword Arguments
• Symbol array literals
• UTF-8 by default
• Scoped Monkey-Patching

11. Keyword Arguments
• Use for named, optional arguments
• No specific order
• Descriptive
• Easy to remember

12. Keyword Arguments
Ruby 1.9:
def self.find_by_division_id(employer_id, opts={})
opts.symbolize_keys!
params = opts.reject { |k,v| v.blank? }
. . .
end

13. Keyword Arguments
What if we want:
• An arbitrary number of opts?
• To have nil as a valid value?
• Descriptive Exceptions?

14. Keyword Arguments
Ruby 1.9:
def log(*msgs)
opt = msgs.last.is_a?(Hash) ? msgs.pop : {}
level = opt.key?(:level) ? opt.delete(:level) : "ERROR"
time = opt.key?(:time) ? opt.delete(:time) : Time.now
raise "unknown key: #{opt.keys.first}" if !opt.empty?
msgs.map do |msg|
puts "#{ time.ctime } [#{ level }] #{ msg }"
end
end

15. Keyword Arguments

16. Keyword Arguments
Ruby 2.0:
def log(msg, level: "ERROR", time: Time.now)
puts "#{ time.ctime } [#{ level }] #{ msg }"
end

17. Symbol Array
Literals
Need a quick array of symbols?
%i(foo bar) # => [:foo, :bar]

18. Scoped monkey
patching
Monkey Patching?

19. monkey patching
• Ruby 1.9 uses Open Class
• Add methods to existing classes
• Replace methods in existing classes
• Example: ActiveSupport

20. monkey patching
What could possibly go wrong?

21. monkey patching
class String
def to_slug(id)
self.truncate(30, separator: ' ', omission: '').
parameterize + "-#{id}"
end
end

22. monkey patching
class String
def to_slug(id)
"#{id}-" + self.truncate(30,
separator: ' ',
omission: '').
parameterize
end
end

23. monkey patching
Global modification is BAD

24. Scoped monkey
patching
Use Refinements!

25. Scoped monkey
patching
module GemName
refine String
def to_slug(id)
. . .
end
end
end

26. Ruby 2.0
Questions?