Sometimes Memoize

A small Ruby library that memoizes method calls or code blocks for the duration of a block call only.

Useful for:

• Long-running processes where the result of a method is expensive to compute, and
• The result is used multiple times within another operation, but
• You'll want to re-compute the result on a subsequent call, or
• A result is cheap to compute but changes quickly, and
• You want to ensure consistency of the value for the duration of another operation

Features:

• Easily turn memoizing on and off. Memoized values are forgotten after it's turned off.
• Annotate existing methods as sometimes memoized
• Wrap code blocks and sometimes memoize the result

Install

$ sudo gem install sometimes_memoize

Summary

require 'sometimes_memoize'
    
class Memoizer
  include SometimesMemoize

  def incrementor
    @counter ||= 0
    @counter += 1
    @counter
  end
  sometimes_memoize :incrementor
    
end

m = Memoizer.new

assert_equal 1, m.incrementor

assert_equal 2, m.incrementor

m.memoizing do
  assert_equal 3, m.incrementor

  assert_equal 3, m.incrementor
end

For a fuller example see test directory.