From: Rick DeNatale <rick.denatale@...>
Date: 2007-09-21T04:41:15+09:00
Subject: Re: Idiomatic Ruby for Array#extract / Range#length?

On 9/20/07, Xavier Noria <fxn@hashref.com> wrote:
> On Sep 20, 2007, at 7:26 PM, Rick DeNatale wrote:
>
> > Getting back to the original thread though, it's actually not quite
> > true that ranges require the starting and ending elements to implement
> >  succ,
>
> Ah, I thought they did because of this excerpt from the Pickaxe:
>
> "So far we've shown ranges of numbers and strings. However, as you'd
> expect from
> an object-oriented language, Ruby can create ranges based on objects
> that you define.
> The only constraints are that the objects must respond to succ by
> returning the next
> object in sequence and the objects must be comparable using <=>."
>
> Also, the documentation of Range says:
>
> "Ranges can be constructed using objects of any type, as long as the
> objects can be compared using their +<=>+ operator and they support
> the +succ+ method to return the next object in sequence."
>
> So, in what sense succ is not required?

http://talklikeaduck.denhaven2.com/articles/2007/09/20/duck-a-la-range

-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/