From: Robert Klemme <shortcutter@...>
Date: 2007-04-03T20:10:07+09:00
Subject: Re: Last iteration condition

On 03.04.2007 10:24, Gary Wright wrote:
> 
> On Apr 3, 2007, at 3:50 AM, Brian Candler wrote:
> 
>> On Tue, Apr 03, 2007 at 03:31:09PM +0900, Gary Wright wrote:
>>> Building off of Brian's suggestion in that thread, here
>>> is a way to provide a 'countdown' as the end of the iteration
>>> approaches.  Default is to only flag the last item but you
>>> can ask for any number of items to be flagged.
>>
>> Interesting. Maybe it would be cleaner to return nil for all 
>> non-countdown
>> items, and then n-1, n-2 ... 0 as the flag (or n, n-1 ... 1). e.g.
> 
> I liked the idea of the flag being true for all but the last item.
> It just makes boolean expressions nicer for that special case even
> when you are counting down.

No need for complex new code, this can be done with #inject very simply:

irb(main):005:0> print "back ", %w{aaa bbb ccc ddd}.inject {|x,y| print 
"front ", x, "\n"; y}, "\n"
front aaa
front bbb
front ccc
back ddd
=> nil

The trick is to use the form without arguments.

Kind regards

	robert