The Beauty of Ruby

# Ruby reads like a wish list
5.times { puts "Hello, world!" }

# Asking real questions
age = 17
puts age.odd?     # → true  (predicate methods end in ?)
puts age.between?(10, 20)  # → true

# Unless is built-in
puts "You're a minor" unless age >= 18

# One-liner conditionals feel like prose
puts "Go to bed!" if Time.now.hour > 22

numbers = [3, 1, 4, 1, 5, 9, 2, 6]

# Transform every element
squares = numbers.map { |n| n ** 2 }
# → [9, 1, 16, 1, 25, 81, 4, 36]

# Filter with intent
evens = numbers.select(&:even?)
# → [4, 2, 6]

# Chain it all — pipeline style
result = numbers
  .select { |n| n > 3 }
  .map    { |n| n * 10 }
  .sum
# → 200

class Integer
  def factorial
    return 1 if self <= 1
    self * (self - 1).factorial
  end

  def seconds; self;         end
  def minutes; self * 60;   end
  def hours;   self * 3600; end
end

puts 5.factorial   # → 120
puts 2.hours        # → 7200

class String
  def palindrome?
    self == self.reverse
  end
end

puts "racecar".palindrome?  # → true
puts "ruby".palindrome?     # → false

# Modern hash syntax — clean and readable
car = {
  make:   "Porsche",
  model:  "911",
  year:   1973,
  color:  "Guards Red"
}

# Safe navigation — no more nil crashes
user = nil
puts user&.name  # → nil  (not an error!)

# Destructuring with pattern matching (Ruby 3+)
case car
in { make: "Porsche", year: (1970..1979) => year }
  puts "Classic air-cooled from #{year}!"
end
# → Classic air-cooled from 1973!

module Driveable
  def drive
    puts "#{self.class} is driving!"
  end
end

module Electric
  def charge
    puts "Plugging in… ⚡"
  end
end

class Car
  include Driveable
end

class ElectricCar < Car
  include Electric
end

tesla = ElectricCar.new
tesla.drive   # → ElectricCar is driving!
tesla.charge  # → Plugging in… ⚡

# Enumerable mixin — mix it in, get 50+ methods free
class Playlist
  include Enumerable

  def initialize(songs)
    @songs = songs
  end

  def each(&block)
    @songs.each(&block)
  end
end

pl = Playlist.new(["Bohemian Rhapsody", "Comfortably Numb", "Hotel California"])
puts pl.min    # → Bohemian Rhapsody (alphabetically)
puts pl.sort.first