Elaine Naomi elainenaomi

Chapter 1 - Object Oriented Design

The purpose of design is to allow you to do design later, and it's primary goal is to reduce the cost of change.

SOLID Design:

Single Responsibility Principle: a class should have only a single responsibility
Open-Closed Principle: Software entities should be open for extension, but closed for modification (inherit instead of modifying existing classes).
Liskov Substitution: Objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program.
Interface Segregation: Many client-specific interfaces are better than one general-purpose interface.

Pry Cheat Sheet

Youtube Tutorial 2013

Command Line

pry -r ./config/app_init_file.rb - load your app into a pry session (look at the file loaded by config.ru)
pry -r ./config/environment.rb - load your rails into a pry session

Debugger

git add -p is your friend

git add -p is basically "git add partial (or patch)"

Patch mode allows you to stage parts of a changed file, instead of the entire file. This allows you to make concise, well-crafted commits that make for an easier to read history. This feature can improve the quality of the commits. It also makes it easy to remove parts of the changes in a file that were only there for debugging purposes - prior to the commit without having to go back to the editor.

It allows you to see the changes (delta) to the code that you are trying to add, and lets you add them (or not) separately from each other using an interactive prompt. Here's how to use it:

from the command line, either use

git add -p

Remove MySQL completely

Open the Terminal
Use mysqldump to backup your databases
Check for MySQL processes with: ps -ax | grep mysql
Stop and kill any MySQL processes
Analyze MySQL on HomeBrew:
```
brew remove mysql
```

Rails naming conventions

General Ruby conventions

Class names are CamelCase.

Methods and variables are snake_case.

Methods with a ? suffix will return a boolean.

When should you use DateTime and when should you use Time?

It's a common misconception that [William Shakespeare][1] and [Miguel de Cervantes][2] died on the same day in history - so much so that UNESCO named April 23 as [World Book Day because of this fact][3]. However because England hadn't yet adopted [Gregorian Calendar Reform][4] (and wouldn't until [1752][5]) their deaths are actually 10 days apart. Since Ruby's Time class implements a [proleptic Gregorian calendar][6] and has no concept of calendar reform then there's no way to express this. This is where DateTime steps in:

>> shakespeare = DateTime.iso8601('1616-04-23', Date::ENGLAND)
=> Tue, 23 Apr 1616 00:00:00 +0000
>> cervantes = DateTime.iso8601('1616-04-23', Date::ITALY)
=> Sat, 23 Apr 1616 00:00:00 +0000

Use these rapid keyboard shortcuts to control the GitHub Atom text editor on macOS.

Key to the Keys

⌘ : Command key
⌃ : Control key
⌫ : Delete key
← : Left arrow key
→ : Right arrow key
↑ : Up arrow key

The Imposter's Handbook

This a collection of interesting links found in The Imposter's Handbook by Rob Conery.

Content:

Introduction
A Little History
The Tools
Customizing The Terminal

Mac OS : Show your git branch name on your bash terminal

⚠️ Does not work in zsh terminal

Add these lines in your ~/.bash_profile file

# Show current git branch name
parse_git_branch() {
     git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/ (\1)/'
}

	defmodule PushButton do
	@behaviour :gen_statem

	@name :pushbutton_statem

	# Client API

	def start do
	:gen_statem.start({:local,@name}, __MODULE__, [], [])
	end