Simple Code- The Simple Life in Software Land -

1Rui Carvalho @rhwy :: rui.fr

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I’m Agile, Should I care?

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Agile Cats

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follow XP rules

Agile Cats

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Complexity is Everywhere

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Complexity is Everywhere

and making things simple is hard!

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The Domain Complexity

Customer needs ‘Foo’

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…You think schema ‘Bar’

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Wrong models cause massive accidental complexity

Greg Young10

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Solving the wrong problem

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« It should go faster ! »

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Change the Engine, problem solved!

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Hidden Technical Complexity

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Frameworks?

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How big ?

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Config > Domain

A framework …

= calls you20

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You

Call

the Library

all that matters!

Bad Understanding Poor design No design

Technology locking

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} Generates Complexity !

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Technical debt is watching you!

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Start simplicity now before it blows you!

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How to start ?

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Remember Agile Principles?

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.

28Kent Beck

the 4 elements of Simple design

• Passes its tests• Minimizes duplication• Maximizes clarity• Has fewer elements

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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

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JbRains

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Simple Design Dynamo

(c) jbrains 2013

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What else ?

Better Naming

Iterate & refactor 33

Remove Duplication

What problem are trying to solve?

Always!34

Avoid coupling

everywhere, from classes to libraries

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Be Consistent

Readability, Rules, Conventions36

Be functional!

Be declarative, Immutable, use lambdas

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Practice !

Practice, Practice, Practice ! …

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Get more Fun

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All you need…http://c2.com/cgi/wiki?

ExtremeProgrammingRoadmap

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http://blog.thecodewhisperer.com/2013/12/07/putting-an-age-old-battle-to-rest/

Simple Design Dynamo

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

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Add-on:

lambda refactoring

43The Silence of the Lambas

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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

}}

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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);

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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 );

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Add-on:

More quotes

There is no good

but some of them are useful

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{ Model | Architecture | persistance }

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“Templates, patterns, frameworks don’t solve anything”

they are just tools to start faster