From: Brian Adkins <lojicdotcom@...>
Date: 2007-10-13T11:45:02+09:00
Subject: Re: range max

On Oct 12, 9:59 pm, Brian Adkins <lojicdot...@gmail.com> wrote:
> On Oct 12, 1:25 pm, "ara.t.howard" <ara.t.how...@gmail.com> wrote:
>
> > On Oct 12, 2007, at 9:40 AM, Brian Adkins wrote:
> > > Actually, what you want is simply N. It's a nonsensical request from a
> > > troll. Using max, end, last, etc. to find the end of the range is
> > > ridiculous since you must know the end of the range to define the
> > > range!
>
> > that is not true.  any object can be used in a range in ruby.  it
> > only must respond to #succ.  it's quite possible to declare classes
> > that worked like so
>
> I'm not unfamiliar with the domain of the Range class. Let's not get
> ridiculous here; I was referring specifically to integer ranges.
> Nothing unambiguates like code, eh? :)
>
> class Range
>   def max_int
>     raise 'invalid range' if self.end < self.begin
>     self.end - (self.exclude_end? ? 1 : 0)
>   end
> end

Actually, I think the following would be better for those rare people
who find themselves frequently wondering what the largest int in a
range is, and would prefer O(1) instead of O(n):

class Range
  alias orig_max max
  def max
    if ( self.begin.kind_of?(Integer) &&
         self.end.kind_of?(Integer) &&
         self.begin <= self.end )
      self.exclude_end? ? self.end - 1 : self.end
    else
      orig_max
    end
  end
end

Now if someone can just come up with a real world example (i.e.
currently existing code in production) of Ruby code that actually
requires this, I'll be amazed. :)