Ruby Struct

Structs: Simple Objects

Objective: Fancy hashes that responds to attributes names as a function, like in JS Objects

Car = Struct.new(:model, :maker, :year, keyword_init: true)

vw_up = Car.new model: 'Up!', year: 2015, maker: 'VW'
polo = Car.new('Polo', 'VW', 2018)
golf = Car.new 'Golf', 'VW'


polo.maker
# "VW"
golf.year
# nil

Equality: It uses their attributes instead object ids like default classes

# vw_up2 = Car.new model: 'Up!', maker: 'VW', year: 2015
vw_up == vw_up2
# True

OpenStruct: Simpler alternative

require 'ostruct'

cat = OpenStruct.new(color: 'black')
puts cat.class
puts cat.color

Differences from Struct

• Struct creates a new class with predefined attributes, equality method (==) & enumerable
• OpenStruct creates a new object with the given attributes