From: "trans.  (T. Onoma)" <transami@...>
Date: 2004-10-10T04:52:54+09:00
Subject: Re: Range behavior (Re: [RCR] New [] Semantics)

On Saturday 09 October 2004 03:25 pm, trans.  (T. Onoma) wrote:
| Note: Consider a special EvenInt class with a succ of: {|x| x+2}, make a
| Range of those and use it as an Array index argument,
|
|    arr = [1,2,3,4,5,6,7,8]
|    arr[EvenInt.new(2)..EvenInt.new(4)]
|
| would you expect [2,3,6,8]? I haven't tried it but my bet is you'll get
| [2,3,4,5,6,7,8] instead.

In fact, I just played with this idea a bit and found Range to be quite out of 
wack:

  class Fixnum
    def succ
      self + 2
    end
  end

  r = 2..14
  => 2..14
  r.to_a
  => [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]
  r.each {|e| print "#{e} "}; puts
  2 3 4 5 6 7 8 9 10 11 12 13 14
  => nil
  r.member?(4)
  => true
  r.member?(3)
  false

Unless I goofed somehow, this is even more evidence that Enumerable is of 
little use in Range. From the looks of it I'm don't think #succ is even being 
used for anything besides the #member? method!!! I assume this is because it 
is trying to optimize for Fixnum.

T.