clean code coding like a professional

Clean CodeCoding like a professional

XPDay Vietnam @ Hanoi May, 2016

Nguyễn Khắc Nhật | Learning Master @ Học Viện Agile

| [email protected]

The snake game

What is the difference?

Good CodeBad Code

Bad code looks like this...

or even this...

Good code looks like this...

or this...

Productivity trend

What is clean code?

“Clean code is simple and direct. Clean code reads like well-written prose. Clean code never obscures the designer’s intent but rather is full of crisp abstractions and straightforward lines of control”

Grady Booch Object Oriented Analysis

What is clean code?

“Clean code can be read, and enhanced by an developer other than its original author. It has unit and acceptance tests. It has meaningful names. It provides one way rather than many ways of doing one thing. It has minimal dependencies,...”

Dave Thomas OTI, Eclipse

What is clean code?

“I could list all of the qualities that I notice in clean code, but there is one overarching quality that leads to all of them. Clean code always looks like it was written by someone who cares...”

Michael FeathersWorking effectively with Legacy Code

What is clean code?

“In recent years I begin, and nearly end, with Beck’s rules of simple code. In priority order, simple code:

Run all the tests;

Contains no duplication;

Express all the design ideas that are in the system

Minimizes the numbers of entities such as classes, methods, functions,...”

Ron JeffriesExtreme Programming Installed

Extreme Programing Adventures in C#

and...

What make bad or good code?

Names Functions Comments Formats

Objects andData Structure

Error Handling

Unit Tests

Boundaries

Classes System ...

Meaningful Names

Naming Rules

Use Intention-Revealing Names

Avoid Disinformation

Make meaningful Distinctions

Use Pronounceable Names

Use Searchable Names

Avoid Encodings

Avoid Mental Mapping

Class Names

Method Names

Don’t Be Cute

Pick One Word per Concept

Don’t Pun

Use Solution Domain Names

Use Problem Domain Names

Add meaningful Context

Don’t Add Gratuitous Context

Try with this code….

and then….

and, how about this...

Functions

Function Arguments

Function Rules

Functions Should be Small

Functions Should Do Only One Thing

One level of Abstraction per Function

Use Descriptive Names

Function Arguments

Have No Side Effects

Command/Query Separation

Prefer Exceptions to Returning Error Codes

Don’t Repeat Yourself

Multiple Returns

Demo with compareTo() method

The beauty of functional programming

Comments

"Don’t comment bad code—rewrite it."

Formats

Formatting

Vertical Formatting

Horizontal Formatting

The team’s rules first!!!

Conventions

Objects andData Structure

Objects and Data structures

Object Data Structure

Law of Demeter

Given method ƒ of class C, ƒ should only call methods of:

● C

● An object created by ƒ

● An object passed as an argument to ƒ

● An instance variable of C

Clean, Clean, Clean

Pair Programming

like this …

CodingDojo

CodeRetreat

THANK YOU!

clean code coding like a professional

Software