From: "David A. Black" <dblack@...>
Date: 2005-02-05T22:13:44+09:00
Subject: Re: Range three dots (was Re: Range#length?!?!?)

Hi --

On Sat, 5 Feb 2005, georgesawyer wrote:

> "Hal E. Fulton" <hal9000@hypermetrics.com> Feb 13, 2003 at 06:45 AM wrote:
>> "Yukihiro Matsumoto" <matz@ruby-lang.org> February 12, 2003 at 9:48 AM
> wrote:
>>> on 03/02/13, Hugh Sasse Staff Elec Eng <hgs@dmu.ac.uk> writes:
>>>> This has always puzzled me, that the longer gap ('..' vs '...') is the
> shorter interval, but it's way too late to change now, and knowing what I
> know of Matz's work, there's going to be a VERY good reason for this!
>
>>> Unfortunately not for this case.  ".." was there first, so only "..."
> was available when I wanted end excluding range. I made up the reason that
> ".. would be used more often, so that it should be shorter", but I myself
> does not feel this is very good reason.
>
>> I would rationalize it this way: .. works the same as in Pascal (the only
> language I know that also has this construct, though there are probably
> others). So the newer behavior gets the newer syntax (...).
>
>> Maybe two weak reasons can be combined to make a stronger one... ;)
>
> I remember it as, the third dot generally is a placeholder for the highest
> inclusive value of the range.

My mneumonic is:

   .. has two letters, so the upper value is "in"
   ... has three, so the upper value is "out"

:-)


David

-- 
David A. Black
dblack@wobblini.net