Why Simple Code matters ? Simplicity is the key for delivering the right software that matter

1. Simple Code
- The Simple Life in Software Land -
1 Rui Carvalho @rhwy :: rui.fr

2. I’m Agile, Should I care?
2

3. 3
Agile Cats

4. 4
Agile Cats
follow XP rules

5. 5
Complexity is Everywhere

6. 6
Complexity is Everywhere
and making things simple is hard!

7. 7
The Domain Complexity

8. Customer needs ‘Foo’
8

9. …You think schema ‘Bar’
9

10. Wrong models cause massive
accidental complexity
Greg Young
10

11. 11
Solving the wrong problem

12. 12
« It should go faster ! »

13. 13
Change the Engine, problem solved!

14. 14
Hidden Technical
Complexity

15. 15
Frameworks?

16. 16

17. 17

18. 18
How big ?

19. 19
Config > Domain

20. A framework …
= calls you
20

21. 21
You
Call
the Library

22. Bad Understanding
Poor design
No design
Technology locking
} Generates
all that matters!
Complexity !
22

23. 23
Technical debt is watching you!

24. 24

25. Start simplicity now before it blows you!
25

26. 26
How to start ?

27. 27
Remember Agile Principles?

28. the 4 XP Simplicity Rules
• Runs all the tests.
• Expresses every idea that
we need to express.
• Says everything Once And
Only Once.
• Has no superfluous parts.
28 Kent Beck

29. the 4 elements of Simple design
• Passes its tests
• Minimizes duplication
• Maximizes clarity
• Has fewer elements
29

30. 2 final rules
Developing strong skills of detecting
duplication, removing duplication,
identifying naming problems, and fixing
naming problems equates to learning
everything ever written about object-oriented
30
JbRains

31. 31
Simple Design Dynamo
(c) jbrains 2013

32. 32
What else ?

33. Better Naming
Iterate & refactor
33
Remove Duplication

34. What problem are trying to solve?
Always!
34

35. Avoid coupling
everywhere,
from classes to libraries
35

36. Be Consistent
Readability, Rules, Conventions
36

37. Be functional!
Be declarative, Immutable, use lambdas
37

38. Practice !
Practice, Practice, Practice ! …
38

39. Get
more
Fun
39

40. All you need…
http://c2.com/cgi/wiki?
ExtremeProgrammingRoadmap
40
Simple Design Dynamo
http://blog.thecodewhisperer.com/2013/12/07/
putting-an-age-old-battle-to-rest/

41. Hand written sketches are by me and can be reused under Creative
Commons licence, other images are owned by their authors and I really
would like to thank them if I found all credits …
41
@rhwy

42. 42
Add-on:
lambda refactoring

43. 43 The Silence of the Lambas

44. 44
interface IPriceCalculator {
double GetPrice(string productReference)
}
class Basket {
IPriceCalculator calculator;
public Basket(IPriceCalculator calculator) {
this.calculator = calculator;
}
public Result AddProduct(
Product product, int quantity) {
Price = calculator.GetPrice(product.Reference);
//other magic here
}
}

45. 45
class UserPriceCalculator : IPriceCalculator
{
public double GetPrice(string productReference)
{ //do some magic stuff here
return price;
}
}
var basket = new Basket(new UserPriceCalculator());
basket.AddProduct(theProduct, 2);

46. 46
class Basket {
public Result AddProduct(
Product product, int quantity,
Func<string,double> calculator) {
Price = calculator(product.Reference);
//other magic
}
}
var basket = new Basket();
basket.AddProduct(theProduct, 2, x=>x.rawPrice*0,85 );

47. 47
Add-on:
More quotes

48. There is no good
but some of them are useful
48
{ Model | Architecture | persistance }

49. 49
“Templates, patterns, frameworks
don’t solve anything”
they are just tools to start faster