require 'memoist'
class Thing
  extend Memoist
  def a
    puts "in a body"
    return 10
    10
  end
  memoize :a

  def b
    puts "in b body"
    nil
  end
  memoize :b

  def c
    puts "in c body"
    10
  end
  memoize :c
end

tt = Thing.new
2.times do |i|
  puts "Iteration: #{i}"
  puts tt.a
  puts tt.b
  puts tt.c
end

# Output:
# Iteration: 0
# in a body
# 10
# in b body
#
# in c body
# 10
# Iteration: 1
# 10
#
# 10