jgaskins

# Luhn Checksum
#  
# http://en.wikipedia.org/wiki/Luhn_algorithm
#  
# Implement a Ruby program that outputs the validity of a number by applying the Luhn Checksum.
#  
# Input:
# The program should accept a single number to validate.
#  
# Output:

jgaskins

require 'bcrypt'

class User
  attr_reader :email, :password
  
  def initialize attributes={}
    @email = attributes[:email]
    @password = BCrypt::Password.create(attributes[:password]).to_s
  end
end

jgaskins

require 'bcrypt'

class HashedPassword < Virtus::Attribute::String
  class Hashed < Virtus::Attribute::Writer::Coercible
    def coerce(value)
      BCrypt::Password.create(value)
    end
  end

  lazy true # No idea what this does. I found it in spec/integration/custom_attributes_spec.rb

jgaskins

require 'bigdecimal'

class Fixnum
  def / other
    BigDecimal.new(self) / other
  end
end

jgaskins

module A
  module B
    C = Class.new
  end
end

def redefine_constant full_const_name, value
  const_path = full_const_name.to_s.split('::')
  namespace = const_path[0..-2].inject(Kernel) { |scope, name| scope.const_get(name) }
  const = const_path[-1]

jgaskins

require 'benchmark'

class C
  def m
  end
end

class D
  def m
  end

jgaskins

class Fibonacci
  attr_reader :fibs, :calls

  def initialize
    @fibs = [0, 1]
    @calls = Hash.new { |h, k| h[k] = 0 }
  end

  def [] position
    calls[position] += 1

jgaskins

class String
  def constantize
    split('::').inject(Kernel, &:const_get)
  end
end

A, A::B = Module.new, Class.new

p "A::B".constantize # => A::B
p "Object".constantize # => Object

jgaskins

require 'benchmark'
require 'prime'

class Integer
  def simple_prime?
    (2..Math.sqrt(self).floor).all? { |i| (self % i).nonzero? }
  end

  def clever_prime?
    return true  if self == 2

jgaskins

require 'benchmark'

class FooProxy
  attr_reader :foo

  def initialize(foo)
    @foo = foo
  end

  def bar