From: Mark Hubbart <discord@...>
Date: 2004-04-13T07:01:41+09:00
Subject: Re: zip block oddities/bug?


On Apr 12, 2004, at 2:39 PM, Simon Strandgaard wrote:

> On Mon, 12 Apr 2004 15:40:06 +0000, Martin DeMello wrote:
>> Note the difference:
>>
>> a.zip(b,c).map {|i| ... } # builds the array, then iterates over it
>> a.zip(b,c) {|i| ... }      # generates values one by one and calls 
>> block
>>
>> If the latter functionality were not built into zip, there'd be no way
>> to do it from 'outside', short of using a continuation. As daz points
>> out, there are definitely times you'd want to iterate without building
>> either an intermediate or an output array.
>
> I think thats a broken metaphor, to do multiway each by means
> of zip.
>
> I don't wanna defend my idea any longer (too much resistance).
> Isn't there any which can say something positive.. or agree with
> me on this ?

I would have to agree with you on this... it doesn't make sense to me 
that the block version doesn't collect the output of yield.

That said, I can definitely see the benefit of having it *not* collect 
the output. I would just tend to think that the non-collecting one 
should not have the same name as the collecting one. Perhaps:

   (4..6).zip(10..12)  #=> [[4, 10], [5, 11], [6, 12]]
   (4..6).zip(10..12) {|a| a[0]*a[1] } #=> [40, 55, 72]

and

   (4..6).zip_each(10..12) {|a| puts a[0]*a[1] } #=> nil

But then this would break a lot. Even if people agree with this, I 
wouldn't expect to see it before 2.0

--Mark