Why should we care about software design? What is emergent design? What does it have to do with showers and why should we do it? Is that Sherlock Holmes?

1. c a k e s , s h o w e r s a n d e l e c t r i c i a n s
EMERGENT DESIGN
Rouan Wilsenach
@rouanw
rouanw.github.io
thoughtworks.com

2. 2
It is not enough for code
to work.
- Robert Martin

3. 3

4. 4

5. WHY DESIGN ?
5

6. 6

7. 7

8. 8

9. 9ANDY GREENBERG/WIRED

10. 10Steve Jurvetson

11. 11
Easy to learn Fast to changeFewer bugs

12. WHY EMERGENT ?
12

13. 13https://www.flickr.com/photos/jshj/4619958228

14. 14https://www.flickr.com/photos/chrisny2/4637837938

15. 15
Build. Measure. Learn.

16. 16
emerge
verb • become apparent
https://www.flickr.com/photos/schnappi/2321628609

17. 17
not
become well-designed
https://www.flickr.com/photos/evaysucamara/5438832695

18. 18
a change made in analysis
for $1 would cost thousands
to fix in production
- The change curve

19. 19
a change made in analysis
for $1 would cost thousands
to fix in production
- The change curve

20. SIMPLICITY
What is good design?
20

21. 21
Why is this so hard?
- Every developer, ever

22. 22
a system made out of genuinely
simple parts, is going to be able to
affect the greatest change with
the least work
- Rich Hickey

23. 23http://martinfowler.com/bliki/BeckDesignRules.html

24. AWAY FROM
!
THE CODE
24

25. 25
Talk about it

26. 26
Draw something

27. 27
Know your challenges

28. 28
Where are we going?

29. 29

30. IN FRONT OF
!
THE CODE
30

31. 31
refactoring
noun • a change made to the
internal structure of software to
make it easier to understand and
cheaper to modify without
changing its observable behaviour
http://martinfowler.com/bliki/DefinitionOfRefactoring.html

32. BEFORE
Preparatory refactoring
32

33. 33
Make the change easy
(warning: this may be hard),
then make the easy change
- Kent Beck

34. 34
You must kill all your
darlings
- William Faulkner

35. DURING
Continuous refactoring
35

36. 36
Don’t forget the last step

37. 37
Talk through it

38. AFTER
Take a step back
38

39. 39
When writing code we
should always be
thinking of the reader
- Martin Fowler

40. 40
Always leave the campground
cleaner than you found it.
- The boy scout rule, Robert Martin

41. 41
Perfect is the
enemy of good.
- Voltaire

42. RECAP
Again! Again!
42

43. 43
Build. Measure. Learn.
Working code is not enough
change the change curve

44. 44
Simplicity

45. 45
In front of
the code
Away from
the code

46. SOME RESOURCES
Articles
• http://martinfowler.com/articles/designDead.html
• http://martinfowler.com/bliki/BeckDesignRules.html
• bit.ly/nf-ead-all (Neal Ford)
Videos
• http://www.infoq.com/presentations/Simple-Made-Easy (Rich Hickey)
• https://vimeo.com/16955608 (Neal Ford)
Books
• http://www.amazon.com/Clean-Code-Handbook-Software-Craftsmanship/dp/0132350882
(Uncle Bob)
• http://www.amazon.com/Extreme-Programming-Explained-Embrace-Edition/dp/0321278658
(Kent Beck)
News
• http://www.wired.com/2015/07/hackers-remotely-kill-jeep-highway/
• http://motherboard.vice.com/en_uk/read/how-is-critical-life-or-death-software-tested
46

47. a m e t a p h o r m a s h - u p
EMERGENT DESIGN
Rouan Wilsenach
@rouanw
rouanw.github.io
thoughtworks.com