Markus' Ruby hangman to implement an LRU function

201306_ruby_hangman_lru

def LRU(n, &b)
  h={}
  ->(*k) do
    h[k] = h.delete(k) do
      puts "cache miss"
      if h.length >= n
        puts "clearing cache past #{n}"
        h.shift
      end
      b[*k]
    end
  end
end

def bar(a,b,c)
  @bar ||= LRU(3) { |a,b,c| a * b * c }
  @bar[a,b,c]
end

puts bar(1,2,3)
puts bar(2,2,3)
puts bar(2,2,3)
puts bar(2,2,3)
puts bar(2,2,3)
puts bar(3,2,3)
puts bar(4,2,3)
puts bar(5,2,3)