exercise 1 by Ray from Rubylearning Metaprogramming Batch 6

exercise_1_by_Ray.rb

results = []

# 3
results << class A
  def initialize
    @a = 11
    @@a = 22
    a = 33
  end
  @a = 1
  @@a = 2
  a = 3
end

my_a = A.new

# 1
results <<  A.instance_variable_get(:@a)


# 11
results << my_a.instance_variable_get(:@a)

# 22
results << A.class_variable_get(:@@a)

# 2
# I had to copy the original class definition otherwise I wouldn't get 2, but 22
# Maybe someone can explain
# class A
#   def initialize
#     
#   end
# end
# 
# puts "wrong results without repeating the original class definition"
# results << A.class_variable_get(:@@a)
class A
  def initialize
    @a = 11
    @@a = 22
    a = 33
  end
  @a = 1
  @@a = 2
  a = 3
end

class A
  def initialize
    
  end
end

results << A.class_variable_get(:@@a)





# 33
class A
  def initialize
    @a = 11
    @@a = 22
    a = 33
  end
  @a = 1
  @@a = 2
  a = 3
end

class B < A
  def initialize
    puts super
  end
end
# => last line ...


results.sort.each do |result|
  puts result
end
# 33 continued
B.new

exercise_1_by_Ray_refined.rb

results = []

# 3
results << class A
  def initialize
    @a = 11
    @@a = 22
    a = 33
  end
  @a = 1
  @@a = 2
  a = 3
end

# 1
results <<  A.instance_variable_get(:@a)

# 2
results << A.class_variable_get(:@@a)

# 11
my_a = A.new
results << my_a.instance_variable_get(:@a)

# 22
results << A.class_variable_get(:@@a)


# 33
class A
  def initialize
    @a = 11
    @@a = 22
    a = 33
  end
  @a = 1
  @@a = 2
  a = 3
end

class B < A
  def initialize
    puts super
  end
end
# => last line ...


results.sort.each do |result|
  puts result
end
# 33 continued
B.new

exercise_1_by_Ray_xfinal.rb

results = []

# 3
results << class A
  def initialize
    @a = 11
    @@a = 22
    a = 33
  end
  @a = 1
  @@a = 2
  a = 3
end

# 1
results <<  A.instance_variable_get(:@a)

# 2
results << A.class_variable_get(:@@a)

# 11
my_a = A.new
results << my_a.instance_variable_get(:@a)

# 22
# The class variable has been changed by running A.new
results << A.class_variable_get(:@@a)


# 33
# Accessing a private method
results << my_a.send(:initialize)


results.sort.each do |result|
  puts result
end