From: Brian Candler <B.Candler@...>
Date: 2003-05-21T19:44:34+09:00
Subject: Re: Strange mod_ruby

On Wed, May 21, 2003 at 04:56:51PM +0900, Dominik Werder wrote:
> > It's because you are wrapped in an anonymous module when you use 
> > mod_ruby,
> > so you just created a new Fixnum class in that module, which has nothing 
> > at
> > all to do with 2.
> >
> > If you put that code into another file and `require' it, it gets added to
> > the root namespace.  I think you can also do something like
> > `2.class.module_eval { ... }', IIRC.
> 
> thank you very much, this one got me really busy the last 2 days :)
> 
> is there a reason for this kind of design?

The main reason is that mod_ruby has a single instance of the Ruby
interpreter for *all* the scripts which are being run under it. If one
script decides to define something in its top-level namespace, you don't
want that thing to appear in the top-level namespace of all other scripts -
it would couple them together too closely, causing hard-to-find bugs.

So each script in run in its own anonymous namespace. But if they 'require'
a library, then that goes into the shared top-level namespace: it doesn't
make sense for each script to have its own copy of the dbi library, for
example.

Cheers,

Brian.