Memoize with alias, redefine

memoize_alias.rb

def expensive_stats(id)
  puts "Executing resource intensive method for ID: #{id}"
  sleep 5
  Time.now
end

alias :expensive_stats! :expensive_stats

def expensive_stats(id)
  @expensive_stats ||= []
  @expensive_stats[id] ||= expensive_stats!(id)
end

puts expensive_stats 3
puts expensive_stats 3
puts expensive_stats 3

puts expensive_stats 7
puts expensive_stats 7
puts expensive_stats 7

puts expensive_stats! 7