From: Christopher Dicely <cmdicely@...>
Date: 2009-03-18T23:51:08+09:00
Subject: Re: Using Fixnum, Strings etc. in Modules

On Wed, Mar 18, 2009 at 6:10 AM, Bram Wijnands <brambomail@gmail.com> wrote:
> I'm stuck on why this occurs. (using jRuby 1.1.5 & Ruby 1.8.6)
>
> I'm trying to use modules to scope certain class overrides, so say the
> String class is changed in ModuleA i don't want it to affect ModuleB.
> But when i try to accomplish this i run in to two things.
>
> First, when creating a Module and overwriting, just for example, the
> reverse method. results in an error:
> module ModuleA
> class String; def reverse;false;end; end
>  p String.new("abc").reverse
> end
>
> Okay, so it creates its own class String instead of taking the core
> class String. Basicly what i want is the module to have it's own set of
> core classes.
>
> Secondly, when using direct instantiation in a module it wont use the
> overwritten class, example:
> module ModuleA
> class String < String; def reverse;false;end; end
> p String.new("abc").reverse
> p "abc".reverse
> end
>
> Results in:
> false
> cba
> Instead of false; false
>
> Could anyone point me in the right drection, thanks in advanced !

I don't think its possible to do exactly what you are trying to do
without fundamentally altering the core of Ruby: you can't, as far as
I know, alter a class only for purposes of calls from a particular
module, and literals will always use the  top level class (::String,
etc.) not <CurrentModule>::String. As your code above shows, you can
just avoid using literals and always use explicit constructor calls in
your module to use the local version.