From: Christopher Dicely <cmdicely@...>
Date: 2008-03-04T11:32:59+09:00
Subject: Re: Question on the Ruby Programming Language Book

And, no, I can't explain why I used this:
--
NAMES.each {|name| yield const_get(name.to_s)}
--

Instead of:
---
INSTANCES.each {|season| yield season}
--

Just trying to make things too complex, I guess.

On Mon, Mar 3, 2008 at 6:28 PM, Christopher Dicely <cmdicely@gmail.com> wrote:
> On Mon, Mar 3, 2008 at 3:44 PM, James Britt <james.britt@gmail.com> wrote:
>  > Bharat Ruparel wrote:
>  >
>  >  > 1  Why do you have to create enumerated objects this way?  This seems a
>  >  > long way off from Ruby's philosophy of being succint.  Just to define a
>  >  > few "object" constants I have to go through this?
>  >  >
>  >
>  >  Well, you can add this method:
>  >
>  >
>  >    def next
>  >       INSTANCES[ (@n+1) % 4]
>  >    end
>  >
>  >
>  >  and then do this:
>  >
>  >
>  >    season = Season::Autumn
>  >    puts season
>  >    puts season.next
>  >    puts season.next.next
>  >
>
>
>  Or, better (in Ruby 1.9) add this instead:
>  ---
>  class Season
>
>   extend Enumerable
>
>   def self.each
>     NAMES.each {|name| yield const_get(name.to_s)}
>     self
>   end
>
>   # more direct than making it sortable by defining a <=> operator,
>   # though you could do that instead.
>   def self.sort(&block)
>     if block then to_a.sort(&block) else to_a end
>   end
>
>  end
>  ---
>  And then try (not really all that useful for seasons, but shows that
>  you've got the full power of Enumerable at hand):
>  ---
>  Season.sort {|s1, s2| s1.to_s <=> s2.to_s}.each {|s| puts s.to_s}
>  Season.sort_by {|season| season.to_s}.each {|s| puts s.to_s}
>  Season.map {|season| season.to_s}.each {|s| puts s}
>  ---
>  And finally (the one I like the most):
>  ---
>  seasons = Season.cycle
>  puts seasons.next
>  puts seasons.next
>  puts seasons.next
>  .
>  .
>  .
>  ---
>  (You can do the same thing to make the class Season an
>  Enumerable in Ruby 1.8, but Ruby 1.9's Enumerators
>  and the Enumerable#cycle method really make this
>  cool, IMO.)
>