Ruby / Advanced

At the advanced level, Ruby programmers dive deeper into metaprogramming, advanced OOP, concurrency, testing, and optimization. These concepts prepare you for building large-scale, production-ready Ruby applications.

1. Metaprogramming

Metaprogramming allows you to write code that can modify or generate other code at runtime. Ruby provides methods like send, define_method, and reflection.

👉 Example:

class DynamicGreeter
  define_method(:greet) do |name|
    puts "Hello, #{name}!"
  end
end

greeter = DynamicGreeter.new
greeter.greet("Ruby")  # "Hello, Ruby!"

class DynamicGreeter
  define_method(:greet) do |name|
    puts "Hello, #{name}!"
  end
end

greeter = DynamicGreeter.new
greeter.greet("Ruby")  # "Hello, Ruby!"

2. Advanced OOP Concepts

Ruby supports inheritance, polymorphism, and encapsulation, which help build scalable applications.

👉 Example:

class Animal
  def speak
    puts "Some sound"
  end
end

class Dog < Animal
  def speak
    puts "Woof!"
  end
end

animal = Animal.new
dog = Dog.new

animal.speak  # "Some sound"
dog.speak     # "Woof!"

class Animal
  def speak
    puts "Some sound"
  end
end

class Dog < Animal
  def speak
    puts "Woof!"
  end
end

animal = Animal.new
dog = Dog.new

animal.speak  # "Some sound"
dog.speak     # "Woof!"

3. Concurrency and Multithreading

Ruby supports threads and fibers for concurrent programming.

👉 Example with Threads:

threads = []

3.times do |i|
  threads << Thread.new do
    puts "Thread #{i} is running"
    sleep(1)
    puts "Thread #{i} is finished"
  end
end

threads.each(&:join)

threads = []

3.times do |i|
  threads << Thread.new do
    puts "Thread #{i} is running"
    sleep(1)
    puts "Thread #{i} is finished"
  end
end

threads.each(&:join)

4. Garbage Collection and Memory Management

Ruby automatically handles memory with its garbage collector, but developers can optimize memory usage with techniques like object re-use and profiling.

👉 Example (Measuring memory):

require 'objspace'

arr = []
1000.times { arr << "memory".dup }

puts ObjectSpace.memsize_of(arr)  # Shows memory size of the array

require 'objspace'

arr = []
1000.times { arr << "memory".dup }

puts ObjectSpace.memsize_of(arr)  # Shows memory size of the array

5. Ruby on Rails Basics

Rails is a popular web framework built on Ruby. It follows the MVC (Model-View-Controller) pattern.

👉 Example (Simple Rails Route):

# In config/routes.rb
Rails.application.routes.draw do
  get 'welcome/index'
end

# In app/controllers/welcome_controller.rb
class WelcomeController < ApplicationController
  def index
  end
end

# In app/views/welcome/index.html.erb
<h1>Hello from Rails!</h1>

# In config/routes.rb
Rails.application.routes.draw do
  get 'welcome/index'
end

# In app/controllers/welcome_controller.rb
class WelcomeController < ApplicationController
  def index
  end
end

# In app/views/welcome/index.html.erb
<h1>Hello from Rails!</h1>

6. Testing in Ruby (RSpec & Minitest)

Writing tests ensures code reliability.

👉 Example with RSpec:

# spec/calculator_spec.rb
require 'rspec'

class Calculator
  def add(a, b)
    a + b
  end
end

RSpec.describe Calculator do
  it "adds two numbers" do
    calc = Calculator.new
    expect(calc.add(2, 3)).to eq(5)
  end
end

# spec/calculator_spec.rb
require 'rspec'

class Calculator
  def add(a, b)
    a + b
  end
end

RSpec.describe Calculator do
  it "adds two numbers" do
    calc = Calculator.new
    expect(calc.add(2, 3)).to eq(5)
  end
end

7. Performance Optimization

Optimizing Ruby code involves reducing memory usage, avoiding unnecessary loops, and using built-in methods efficiently.

👉 Inefficient vs Optimized Example:

# Inefficient
result = []
[1,2,3,4,5].each { |n| result << n * 2 }

# Optimized
result = [1,2,3,4,5].map { |n| n * 2 }

puts result.inspect  # [2, 4, 6, 8, 10]

# Inefficient
result = []
[1,2,3,4,5].each { |n| result << n * 2 }

# Optimized
result = [1,2,3,4,5].map { |n| n * 2 }

puts result.inspect  # [2, 4, 6, 8, 10]

✅ With these advanced concepts, you are ready to build high-performance Ruby applications. Whether you aim to master Rails web apps, delve into metaprogramming, or optimize for large-scale systems, Ruby provides powerful tools to take your skills to the next level.