NumericMemoist

The memoize library allows you to cache methods for Numerics (Integer/Float) in Ruby >= 2.0.0.

Installation

Add this line to your application's Gemfile:

gem 'numeric_memoist'

And then execute:

$ bundle

Or install it yourself as:

$ gem install numeric_memoist

Usage

Open class Integer/Float, extend NumericMemoist like the following:

require 'numeric_memoist'

class Integer
  extend NumericMemoist

  def sq
    self ** 2
  end
  memoize :sq
end

Then Integer#sq will only be calcurated once. (These work on Ruby >= 2.0.0, and also <= 1.9.x.)

Comparison to others

On Ruby <= 1.9.x, you may code as follows:

class Integer
  def sq
    @sq ||= self ** 2
    # This raises RuntimeError on Ruby >= 2.0.x
  end
end

This doesn't work on Ruby >= 2.0.0, since Integer is frozen.

You may use another similar gem like Memoist:

require 'memoist'

class Integer
  extend Memoist

  def sq
    self ** 2
  end
  memoize :sq
  # No Error raised, but momeize doesn't work on Ruby >= 2.0.x
end

This doesn't work on Ruby >= 2.0.0 for the same reason.

For newer Rubies

NumericMemoist works well with Ruby 2.4.0 (tested with 2.4.0-preview2).
An old example (bundled with NumericMemoist v0.0.1) does not work with Ruby >= 2.4.0 (for Integer's specification change). Updated example(s) in NumericMemoist >= v0.0.2 .

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

Acknowledgements

Inspired by Memoist.

License

Under the MIT License.