From: Ara.T.Howard@...
Date: 2004-10-01T00:55:01+09:00
Subject: Re: Range syntax theory

On Thu, 30 Sep 2004, gabriele renzi wrote:

> actually, I thought till one moment ago that ... was going to be deprecated.
> I looked up and found that I misremembered this:
> http://www.rubyist.net/~matz/slides/rc2003/mgp00025.html
>
> I'd strongly advocate the elimination of z...y .  It is completely non
> obvious, and it has no advantage _i can see_ over x..k .

programming using the 'offset, length' paradigm lead to much more elegant code
than a 'start, end' paradigm and is used everywhere because of it.  consider

   words = %w( one two three four )

   #
   # process elements two at a time
   #

     len = 2
     r = 0...(a.size / 2)
     r.each{|off| p words[off, len]}

   # vs

     len = 2
     r = 0..((a.size / 2) - 1)
     r.each{|off| p words[off, len]}

   #
   # process first/last half of a
   #
     n = words.size
     a = 0
     b = n / 2

     puts "first #{ b }"
     (a...b).each{|i| p words[i]}

     puts "last #{ b }"
     (b...n).each{|i| p words[i]}

   # vs

     puts "first #{ b }"
     (a..(b - 1)).each{|i| p words[i]}

     puts "last #{ b }"
     (b..(n - 1)).each{|i| p words[i]}


in short i think we'd since an instant rush of 'off by one' errors if ruby
disallowed the '...' operator and obfusicate many elegant algorithims which
follow this paradigm.

regards.

-a
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