From: "Marcel Molina Jr." <marcel@...>
Date: 2006-11-15T15:50:46+09:00
Subject: Re: Design problem with 'inject'

On Wed, Nov 15, 2006 at 03:46:44PM +0900, Gary Boone wrote:
> Ruby's inject has a design that can lead to hard to find bugs. The 
> problem is that you don't have to specify what is summed; the value of 
> the block is summed. That means 'next' can lead to a bug. Here's an 
> example:
> 
> No problem:
> 
>    arr.inject(0) do |sum, i|
>                     sum += i
>                  done
> 
> But suppose you need to skip some elements, so you add a 'next' 
> statement.
> Problem:
> 
>    arr.inject(0) do |sum, i|
>                    next if (i==3)
>                    sum += i
>                  done

You need to do this:

  next sum if i == 3

Also:

  sum += 1 

This unecessarily modifies the sum. 

  sum + 1

Will suffice.

marcel
-- 
Marcel Molina Jr. <marcel@vernix.org>