From: "Chr. Rippel" <chr_news@...>
Date: 2002-01-12T01:04:27+09:00
Subject: Re: class name reported differently in different contexts

"ts" <decoux@moulon.inra.fr> wrote in
....
>  For me, this patch make classid useless but it's not remove it.

From the point of view of someone who is pretty much clueless about
the inner workings of the interpreter it seems that classid and classpath
are normally hidden variables used in computing the value of Class#to_s
Class#inspect (short of overriding the ladder two methods) computed at
most once during the lifetime of a class. Normally this happens when
the interpreter for the first time sees the lines

module Outer
  class Klass
  # body
  end
end

The other possibility is that you define

module Outer
  klass = Klass = Class.new
  # at this point neither classid nor classpath
  # are set - i.e.
  # remove_const :Klass
  # p klass # => Class:0xa047208>
  klass.inspect
  # classid and classpath are computed once never to be changed again,
  # thus
  p klass  # => Outer::Klass
end

Here is another illustration on how classid and classpath (don't quite)
work (as one might expect;-)

(2.0).instance_eval do
  class B; end
  p B # => Float::B
  def Float.inspect ; "no effect on B.inspect - i.e." end
  p type # => no effect on B.inspect - i.e.
  p B # => Float::B
end

IMO it would sort of make sense that neither classid nor classpath are
set before the hook call to #inherited - i.e. the illustrative snippet

class Base
  def self .inherited sub_klass
    puts "#{sub_klass} is inherited form #{self}"
  end
  class Sub < Base; end
end

would result in something like

#=> <Class:0xa047208> is inherited form Base

The previous half-baked solution of setting classid but not classpath
seems like the worst of all possible choices to me.

/Christoph