From: Drew Olson <olsonas@...>
Date: 2008-03-08T06:38:53+09:00
Subject: Re: ActiveSupport Enumerable#sum should not use #size

Stefan Lang wrote:
> inject takes the identity as first parameter:
> 
>     inject(identity) { |sum, element| sum + element }
> 
> and since they define Symbol#to_proc, this can even be
> 
>     inject(identity, &:+)
> 
>>       end
>>     end
>>
>>  Look right?
>>
>>
>>  T.
> 
> Stefan

This is very concise, but doesn't have the same behavior as the original 
sum. This will start any sum with the identity and then build on it from 
there. Not that this is incorrect behavior, it's just different from 
what was originally defined. For example:

a = [1,2,3]

original sum, with identity = 10, would return 6, whereas your version 
would return 16.

- Drew
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