https://github.com/adamcooke/memist

A Ruby Memoization Helper
https://github.com/adamcooke/memist

Last synced: 13 days ago
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A Ruby Memoization Helper

• Host: GitHub
• URL: https://github.com/adamcooke/memist
• Owner: adamcooke
• License: mit
• Created: 2015-07-22T12:10:50.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2019-12-02T10:41:11.000Z (almost 5 years ago)
• Last Synced: 2024-05-12T01:42:53.831Z (6 months ago)
• Language: Ruby
• Homepage: https://adamcooke.io/memoization-in-ruby/
• Size: 21.5 KB
• Stars: 76
• Watchers: 4
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
# Memist

Memist is a tiny library to help with memoizing values in Ruby classes. There

are many other memoization libraries around but Memist provides more invalidation

than others. Let's jump right into a demonstration.

```ruby

class Person

  include Memist::Memoizable

  attr_accessor :first_name, :last_name, :date_of_birth

  def age

    Age.from_date_of_birth(date_of_birth)

  end

  memoize :age

  # Memist can also cache the results from methods that accept a single

  # argument. The cache will be based on the argument provided.

  def tweets(username)

    Twitter.tweets_for_username(username)

  end

  memoize :tweets

end

```

Here you can see we have a method called `age` which generates a person's age

based on on their `date_of_birth`. It returns an integer. Each time we run this

method, we don't want to go to the extra power of calcuating the age, so we

want to cache the value for this instance. To do this, we just add the `memoize`

method to our object.

```ruby

person = Person.new

person.date_of_birth = Date.new(1986, 6, 10)

person.age      #=> 29 (retrieved by calculation)

person.age      #=> 29 (retrieved from the cache based)

```

## Installation

Simple. Just add the gem to your Gemfile.

```ruby

gem 'memist', '~> 2.0'

```

## Usage

Firstly, include `Memist::Memozation` in any class you wish to add memoization to. Then, you need to specify which fields you want to be memoized in your objects. You

do this by calling `memoize` as shown above.

#### Other handy methods

```ruby

person = Person.new

person.date_of_birth = Date.new(1986, 6, 10)

# Access the raw underlying without any memoization

person.age_without_memoization    #=> 29

# Clear the cache for all methods on the model

person.flush_memoization

# Clear the cache for a single method on the model

person.flush_memoization(:age)

# Find out of a vale is memoized or not? When the value has been returned from

# memoized cache, it will be true otherwise it will be false.

person.memoized?(:age)    #=> false

person.memoized?(:age)    #=> true

# Disable memoization for all calls to memoized methods for a

# block of code

person.without_memoization do

  person.age                #=> 29 [no cache]

  person.memoized?(:age)    #=> false

  person.age                #=> 29 [no cache]

end

```