From: Robert Dober <robert.dober@...>
Date: 2007-02-20T04:15:50+09:00
Subject: Re: The peak of the iceberg, was Range cannot loop down and RCR Integer#pred

On 2/19/07, Daniel Schierbeck <daniel.schierbeck@gmail.com> wrote:
> On Mon, 2007-02-19 at 18:14 +0900, Robert Dober wrote:
> > Hi all
> >
> > I was just following the thread about "loop cannot count down" and
> > was about to propose a monkey patched method which might have been
> > convenient for the poster.
> >
> > Like e.g. Range#each_down  (bad name I know).
> >
> > The point is, I cannot, because Range#each is based on succ, and
> > Range#each_down would be based on pred.
> >
> > I just wonder if it might not be a good idea to define pred for all
> > core classes for which succ is defined. I kind of feel stupid not
> > having suggested that in the first place, now :(.
> > (http://rcrchive.net/rcrs/6)
> >
> > Opinions?
>
> It seems you beat me to it :)
Really my fault, I did not discuss it on the list, I did announce it
though, because it seemed so simple.
AAMOF Matz accepted it surely because of its simplicity.
Really a mistake of mine because it could have been discussed for many
more classes and its impact on Ranges.

Maybe you would like to lead discussion about this one, as I stole the
other one from you ;) ?
>
> I'm sure it's been brought up before, and it will surely add more
> complexity
But I do not advocate any usage of #pred, I just advocate its presence.
The user has the power than :)
>to a problem that seems relatively small,
I am not really sure it is that small, this unidirectionality seems
somehow incorrect to me and what I said in the beginning really
bothers me

I cannot iterate through a Range in the reverse sense.

> based on the low
> volume of posts on it here on the mailing list.
It is not an issue for most of us I did not run into it in two years
of Ruby Programming but now that it was brought up for me an iceberg
emerged. ;)
>
>
> Cheers,
> Daniel
>

Robert


-- 
We have not succeeded in answering all of our questions.
In fact, in some ways, we are more confused than ever.
But we feel we are confused on a higher level and about more important things.
-Anonymous