Memo::It
Clever memoization helper that uses Ruby internals instead of meta-programming.
Usage
Requiring the gem will add a memo
method to the Object
class so that you can just use it like so:
def load_stuff_from_the_web
memo do
# some expensive operation like HTTP request
# the return value of the block will be memoized
HTTPClient.get('https://github.com/phoet/memo-it')
end
end
In case you want to memoize something that has parameters, memo-it will just use all local variables in scope to determine the memoization:
def load_repo(name = 'memo-it')
memo do
# in this case the result will be memoized per name
HTTPClient.get("https://github.com/phoet/#{name}")
end
end
If, on the other hand, you want to memoize parameters but ignore one of them,
you can do this by adding it to the :except
list:
def load_repo(name = 'memo-it', time = Time.now)
memo(except: :time) do
# in this case the result will be memoized per name
HTTPClient.get("https://github.com/phoet/#{name}?time=#{time}")
end
end
Or provide a list of parameters to except:
def load_repo(name = 'memo-it', time = Time.now, other = 'irrelevant')
memo(except: [:time, :other]) do
# in this case the result will be memoized per name
HTTPClient.get("https://github.com/phoet/#{name}?time=#{time}&other=#{other}")
end
end
To be symmetric, it's also possible to define one or more parameters through the :only
key:
def load_repo(name = 'memo-it', time = Time.now, format = 'json')
memo(only: [:name, :format]) do
# in this case the result will be memoized per name & format
HTTPClient.get("https://github.com/phoet/#{name}?time=#{time}&format=#{format}")
end
end
In case you would like to disable memoization (ie testing) you can disable Memo::It:
# enabled is default
Memo.enabled? # => true
# disable memoization globally
Memo.disable
Memo.enabled? # => false
# re-enable memoization
Memo.enable
Memo.enabled? # => true
Installation
As a Gem
Add this line to your application's Gemfile:
gem 'memo-it'
And then execute:
$ bundle
Or install it yourself as:
$ gem install memo-it
Copy & Paste
If you don't want to include yet another Gem, just run this in your shell:
$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/phoet/memo-it/master/bin/install)"
Development
After checking out the repo, run bin/setup
to install dependencies. Then, run rake test
to run the tests. You can also run bin/console
for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install
. To release a new version, update the version number and then run bundle exec rake release
, which will create a git tag for the version, push git commits and tags, and push the .gem
file to rubygems.org.
Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/phoet/memo-it. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
License
The gem is available as open source under the terms of the MIT License.