Mem

Memoize method calls.

Installation

Install the gem and add to the application's Gemfile by executing:

bundle add mem

If bundler is not being used to manage dependencies, install the gem by executing:

gem install mem

Usage

class Foo
  include Mem

  def initialize
    @count = 0
  end

  def bar
    baz
  end

  # `memoize` defines bar_with_memoize & bar_without_memoize,
  # and the result of the 1st method call is stored into @memoized_table.
  memoize :bar

  private

  def baz
    @count += 1
  end
end

foo = Foo.new
foo.bar #=> 1
foo.bar #=> 1
foo.bar #=> 1
foo.has_memoized?(:bar) #=> true
foo.memoized(:bar) #=> 1
foo.memoized_table #=> { bar: 1 }

core ext

You can require "mem/core_ext" to skip include Mem, while this extends Object class.

require "mem/core_ext"

class A
  def x
    puts 1
  end
  memoize :x
end

a = A.new
a.x #=> 1
a.x #=> nothing logged out
a.x #=> nothing logged out