From: "trans.  (T. Onoma)" <transami@...>
Date: 2004-10-12T11:15:46+09:00
Subject: Re: Ruby Directions (was Re: quality of error messages)

On Monday 11 October 2004 09:32 pm, David A. Black wrote:
| With all the recent talk about ranges (much, but not all, of which
| I've read), I've been trying to put my finger on why I find the idea
| of a mutable Range sort of paradoxical.  I'm far from having any kind
| of sound theoretical grounding or rationale... but anyway:
|
| I think of a range as kind of a fact.  For example:  (0..10) is "the
| fact of being between 0 and 10, inclusive".  In which case, changing
| *that fact* -- e.g., having "the fact of being between 0 and 10"
| *itself* become "the fact of being between 6 and 12" -- makes no
| sense.  I guess I think of ranges almost more like numbers; it would
| make sense to me if (0..10) were literally the same object everywhere
| it appeared.
|
| Anyway, all very speculative, but kind of interesting (to me at least

I've been in the trenches with Ranges for the last couple of days. I didn't 
grasp the above fact on my own, but when you brought it up originally it made 
instant sense to me. An Interval (what Ruby calls a Range) is defined solely 
by its sentinels and their exclusivity. So 0..10 is always the same 0..10, 
just as 10 is always the same 10. It's a Multiton --a Singleton based on 
multiple parameters.

T.