Constants and Namespaces

Modules can group constants and classes under a qualified name.

constants_namespaces.rb

module Store
  TAX_PERCENT = 8

  class Calculator
    def self.total(subtotal)
      subtotal + subtotal * TAX_PERCENT / 100
    end
  end
end

subtotal = 
total = Store::Calculator.total(subtotal)

puts "tax_percent=#{Store::TAX_PERCENT}"
puts "subtotal=#{subtotal}"
puts "total=#{total}"

module Store
  TAX_PERCENT = 8

  class Calculator
    def self.total(subtotal)
      subtotal + subtotal * TAX_PERCENT / 100
    end
  end
end

subtotal = 
total = Store::Calculator.total(subtotal)

puts "tax_percent=#{Store::TAX_PERCENT}"
puts "subtotal=#{subtotal}"
puts "total=#{total}"

module Store
  TAX_PERCENT = 8

  class Calculator
    def self.total(subtotal)
      subtotal + subtotal * TAX_PERCENT / 100
    end
  end
end

subtotal = 
total = Store::Calculator.total(subtotal)

puts "tax_percent=#{Store::TAX_PERCENT}"
puts "subtotal=#{subtotal}"
puts "total=#{total}"

namespace A module name can act as a namespace for constants and classes that belong together.