From: Bertram Scharpf <lists@...>
Date: 2009-08-03T09:11:11+09:00
Subject: Re: Inconsistency in Array#[]

Hi,

Am Montag, 03. Aug 2009, 05:50:10 +0900 schrieb Wojciech Piekutowski:
> Disclaimer: I know what docs say, but I'd prefer a different
> behaviour. I want to understand why this design decision was made.
> 
>   a = [1,2,3,4,5]
>   a[-10,10]          #=> nil
> 
> I got nil, but looking from -10 to 0 there are 5 elements, in
> other words in the range (-10, 0> there are 5 elements, like in case
> 1.
> 
> I expected I'd get the same result as in 1 (yes, no additional nils,
> just the whole array). I think this isn't really complying with the
> principle of the least surprise.

In the end, it is probably a matter of taste but I agree with you.
I would even prefer a behaviour like this:

  a[3,-3]    #=> [4,3,2]

This would be the least surprise to me.

I'm pleading for years for an `Array#notempty?' method analogous
to `Numeric#nonzero?' which would be a one-liner in C. But that
seems to be a real imposition on the developers community.

Bertram



________________________________________________________________

VALUE rb_ary_notempty( ary)
    VALUE ary;
{
    return RARRAY( ary)->len == 0 ? Qnil : ary;
}

-- 
Bertram Scharpf
Stuttgart, Deutschland/Germany
http://www.bertram-scharpf.de