Addy

Allows pretty summations. Instead of writing:

(1..5).inject(0) do |memo, num|
  memo + (num**num)
end

You write:

sum(1..5) do |num|
  num**num
end

Personally, I would rather write the latter.

Install the gem:

gem install addy

Then use it!

require 'addy'

class MyClass
  #include it in a class or in Object to get it everywhere
  include Addy
  
  def my_awesome_adder(range)
    sum(range)
  end
end

When you include addy on a class that implements inject, you don't even need to pass a value to it. Instead it calls sum on your class.

require 'addy'

class MyClass < Range
  include Addy
  
  def my_awesome_adder
    sum
  end
end

You can call either sum or summation. They're aliases for the same thing.

Note: The following assumes Addy is included into Range.

When you pass a block to sum it will execute the block on the current number before adding it to the sum.

sum(1..5) {|num| num + 1}  #=> 20
(1..5).sum {|num| num + 1} #=> 20

You don't have to pass a block though!

#this
sum(1..5)              #=> 15
#and
(1..5).sum             #=> 15

#are equivalent to
sum(1..5) {|num| num}  #=> 15
#and
(1..5).sum {|num| num} #=> 15

Ranges and numeric arrays both work well.

sum(1..5)         #=> 15
sum([1,2,3,4,5])  #=> 15

• Fork the project.
• Make your feature addition or bug fix.
• Add tests for it. This is important so I don't break it in a future version unintentionally.
• Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
• Send me a pull request. Bonus points for topic branches.

Copyright (c) 2010 Allen Madsen. See LICENSE for details.

PS: Isn't it ridiculous how much documentation I wrote for one function?