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We write code

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Isn't it more about reading?

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Written once – read many times

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„(…) when you program, you have to think about how someone will read your code, not just how a computer will interpret it.“ Kent Beck

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Not about Architecture

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Methods & Code

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Extra effort

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Save time

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Your code base?

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No content

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It's about joy!

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Code is read many more times than written Tobias Pfeiffer @PragTob pragtob.wordpress.com

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Sources

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Crazy?

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Are comments a smell?

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Outdated comments are the worst

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The why not the what

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Comments are an excuse of the code that it could not be clearer.

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# do one thing … … … # do another thing … … … # do something more … …

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Extract Methods

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do_one_thing do_another_thing do_something_more

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# context, outlet, times, time per step, state, data def pattern(c, o, t, l, s, d) # … end

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Explanatory and meaningful names

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def pattern(context, outlet, time, time_per_step, state, data) # … end

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Try to keep it to 2 parameters

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Argument order dependency

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No magic numbers

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Explanatory variable

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Short Methods (<= 8 LOC)

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# allowed to drink? if customer.age > 18 say 'Okay' prepare_drink requested_drink say 'here you go' hand_drink_over drink, customer else say 'I am sorry you are not legally allowed rather to drink here' say "Would you rather have a #{NON_ALCOHOLIC_DRINKS.sample}?" end

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# allowed to drink? if customer.age > 18 say 'Okay' prepare_drink requested_drink say 'here you go' hand_drink_over drink, customer else say 'I am sorry you are not legally allowed rather to drink here' say "Would you rather have a #{NON_ALCOHOLIC_DRINKS.sample}?" end

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Query method

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Intention revealing method

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# … text.color = red # …

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def highlight(text) text.color = red end

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# … highlight(text) # …

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if customer.age > 18 say 'Okay' prepare_drink requested_drink say 'here you go' hand_drink_over drink, customer else say 'I am sorry you are not legally allowed rather to drink here' say "Would you rather have a #{NON_ALCOHOLIC_DRINKS.sample}?" end

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if customer.age > 18 say 'Okay' prepare_drink requested_drink say 'here you go' hand_drink_over drink, customer else say 'I am sorry you are not legally allowed rather to drink here' say "Would you rather have a #{NON_ALCOHOLIC_DRINKS.sample}?" end

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if customer.age > 18 say 'Okay' prepare_drink requested_drink say 'here you go' hand_drink_over drink, customer else say 'I am sorry you are not legally allowed rather to drink here' say "Would you rather have a #{NON_ALCOHOLIC_DRINKS.sample}?" end

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if customer.age > 18 say 'Okay' prepare_drink requested_drink say 'here you go' hand_drink_over drink, customer else say 'I am sorry you are not legally allowed rather to drink here' say "Would you rather have a #{NON_ALCOHOLIC_DRINKS.sample}?" end

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if allowed_to_drink_alcohol?(customer) serve_drink requested_drink, customer else propose_non_alcoholic_drink end

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„The easiest code to understand is the code you don't have to read at all.“ Tom Stuart (Berlin)

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Same level of abstraction in a method

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prepare_drink requested_drink price = requested_drink.price Check = Check.new check.add_price price say 'That whill be ' + check.total

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prepare_drink requested_drink price = requested_drink.price Check = Check.new check.add_price price say 'That whill be ' + check.total

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prepare_drink requested_drink price = requested_drink.price Check = Check.new check.add_price price say 'That whill be ' + check.total

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prepare_drink requested_drink prepare_check requested_drink

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DRY

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Nice code formatting

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@left ||= 0 @top ||= 0 @width ||= 1.0 @height ||= 0

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double character: 'something weird', stateMask: CTRL | modifier, KeyCode: character.downcase.ord

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80 character Width limit

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80 character Width limit

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80 character Width limit

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80 character Width limit

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80 character Width limit

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Don't program by coincedence

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Code bases detoriate

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No broken windows

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No content

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No content

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Magical time?

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The Boyscout Rule

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TDD

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80% Code Coverage

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20% is never executed

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„Incoming messages should be tested for the state they return. Outgoing command messages should be tested to ensure they get sent. Outgoing query messages should not be tested.“ Sandi Metz

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Know when to break the rules

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If you still like your code from two years ago, then you are not learning fast enough.

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Enjoy Coding! Tobias Pfeiffer @PragTob pragtob.wordpress.com

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Sources ● The Pragmatic Programmer ● Smalltalk Best Practice Patterns ● Clean Code ● Practical Object Oriented Design in Ruby

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Photo Credit ● http://officeimg.vo.msecnd.net/en-us/images/MP900439313.jpg ● http://officeimg.vo.msecnd.net/en-us/images/MC900021328.wmf ● (CC BY-SA 2.0) – http://www.flickr.com/photos/83633410@N07/7658272558/in/photostream/ – http://www.flickr.com/photos/83633410@N07/7658165122/ – http://en.wikipedia.org/wiki/File:Kent_Beck_no_Workshop_Mapping_XP.jpg ● (CC BY-NC-ND 2.0) – http://www.flickr.com/photos/andih/86577529/ – http://www.flickr.com/photos/12584908@N08/3293117576/ – http://www.flickr.com/photos/jasonlparks/4525188865/ – http://www.flickr.com/photos/20714221@N04/2293045156/ ● http://www.flickr.com/photos/47833351@N02/5488791911/(CC BY-ND 2.0) ● (CC BY 2.0) – http://www.flickr.com/photos/barry_b/76055201/ – http://www.flickr.com/photos/25165196@N08/7725273678/ – http://www.flickr.com/photos/29254399@N08/3187186308/ ● (CC BY-NC-SA 2.0) – http://www.flickr.com/photos/dolescum/7380616658/ – http://www.flickr.com/photos/antonkovalyov/5795281215/ – http://www.flickr.com/photos/doug88888/2792209612/ ● (CC BY-NC 2.0) – http://www.flickr.com/photos/37996583811@N01/5757983532/ – http://www.flickr.com/photos/sevendead/5650065458/

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Source pictures ● http://imagery.pragprog.com/products/59/tpp.jpg ● http://www.informit.com/ShowCover.aspx?isbn=9780132852111&type=f ● http://coding-in.net/blog/wp-content/uploads/clean_code.jpg ● http://www.informit.com/ShowCover.aspx?isbn=9780321721334&type=f ● http://mendicantuniversity.org/images/logo.png