From: Mauricio Fernandez <mfp@...>
Date: 2006-05-06T19:50:33+09:00
Subject: Re: Sharp knives and glue

On Sat, May 06, 2006 at 06:20:54PM +0900, Alex Young wrote:
> $ ruby -r freeze-core -e 'class String; def len; "foo"; end; end'
> -e:1: can't modify frozen class (TypeError)
...
> >>I'll work on some 'lock-down' code that will allow classes to lock
> >>themselves down from external modification (not Foo.freeze, but 
> >>something more granular.)
    =======================

> It also struck me that the require mechanism could be hijacked to 
> enforce per-file namespacing to give something like Python's system, 
> which seems to work fairly well.  A require_ns() that wraps a module 
> named after the filename around the code it includes...  Would that help?

Several implementations have been proposed on ruby-talk before; they failed
in cases like

$ cat bad.rb 
::String.class_eval do
#  forces top-level, defies our efforts to wrap it
  def size; 0 end
end
$ cat naive.rb 

a = "foo"
p a.size
load("bad.rb", true)
p a.size
p $"

$ ruby naive.rb 
3
./bad.rb:3: warning: method redefined; discarding old size
0
[]

See http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/27417 for
another proposal.

-- 
Mauricio Fernandez  -   http://eigenclass.org   -  singular Ruby