What is good code? Evaluating Code Quality (workshop)

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What is good code? Evaluating code quality Daniel Carral Barcelona on Rails (@ XING), 02/15/2018

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github.com/dcarral/good-code

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Agenda ➔ Intro ➔ Craft Let’s solve the problem! ➔ Show & discuss Which approach did you use? Why? ➔ Evaluate Opinion vs facts What do the numbers say? ➔ Retrospective

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What is good?

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Good?

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Good? Better?

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Craft Coding Dojo

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How many dojos?

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TDD & refactoring

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Pair programming

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Simple design

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Kata 99 bottles of beer

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Clone & code :) github.com/dcarral/99bottles-polyglot

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(until 20:30h) Clone & code :) github.com/dcarral/99bottles-polyglot

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Time over :)

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Show & discuss (or not ;)

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How did you solve it? Why? Reminder The goal is not to judge our coding skills. We’re discussing how to evaluate code quality.

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github.com/dcarral/99bottles-solutions

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Agenda ➔ Intro ➔ Craft Let’s solve the problem! ➔ Show & discuss Which approach did you use? Why? ➔ Evaluate Opinion vs facts What do the numbers say? ➔ Retrospective

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Evaluating code quality

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Based on opinion

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In your opinion, what is “good code”? ● “Easy to understand and read. Easy to test.” ● “SOLID” ● “Passes the squint test :)” ● “Quality transcends description”

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Based on facts

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Software metrics “A software metric is a standard measure of a degree to which a software system possesses some property.”

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Why measure? “You cannot control what you cannot measure.”* — Tom DeMarco * Apparently, he regrets having said this (thanks David!)

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Some metrics ● Ca 1960: LOC ● 1976: Cyclomatic complexity ● 1997: ABC size

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ABC ● Assignments ● Branches (of control) ● Conditions

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“Confessions of a Ruby Sadist”

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4 more solutions

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What do the numbers say? Solution LOC Flog total Flog worst bit #1 Incomprehensibly concise 19 42.5 36.2 (#verse) #2 Speculatively general 63 54.8 28.5 (lambdas) #3 Concretely abstract 92 67 15.3 (#challenge) #4 Shameless green 34 25.6 19.3 (#verse)

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Why metrics? “Metrics are fallible but human opinion is no more precise. Checking metrics regularly will keep you humble and improve your code.” — Sandi Metz, Katrina Owen

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sandimetz.com/99bottles/postcard

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* Disclaimer: Some people don’t like it (at all). Think twice before purchasing it ;)

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Retro time

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… surprised me. I’ve learnt… I’d like to start doing… Feedback :)

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● Coding dojos ● TDD ● Refactoring ● Pair programming ● Simple design ● Zen & the art of motorcycle maintenance ● Clean Code ● eXtreme Programming explained ● 99 bottles of OOP ● Beautiful code ● Software metrics ● LOC ● Cyclomatic complexity ● ABC size @dcarral dcarral.org