From: Gregory Seidman <gsslist+ruby@...>
Date: 2006-05-17T23:11:10+09:00
Subject: Re: Dynamically modifying modules to avoid namespace collisi

On Wed, May 17, 2006 at 09:34:34AM +0900, Logan Capaldo wrote:
[...]
} One does not require modules, one requires files. One file may have  
} many modules in it, or none. Regardless one can still 'require' that  
} file.
} 
} One way to hack something so it gets stuck in a module is:
} 
} module Protect
}   eval(File.read("path/to/file.rb"))
} end
} 
} Then you access all the classes defined in file.rb like:
} 
} Protect::Node.new # etc.

This is a great idiom, but it needs to be able to function as a (nearly)
drop-in replacement for require. This means that I need to be able to find
the file in the search path that require would normally use. Consider the
following:

def find_require_file(filename)
  # NEED IMPLEMENTATION HERE
end

def namespace_get(str)
  str.to_s.split("::").inject(Object) { |ns,name| ns.const_get(name) }
end

def require_within(module_name, filename)
  file = find_require_file(file)
  mod = module_name
  case module_name
    when Module,Class
      #noop
    else
      mod = namespace_get(mod)
  end
  mod.instance_eval { eval File.read(file) }
end

This is untested, and I don't know how to implement that find_require_file,
but the idea is that the following should work:

module Foo
  module Bar
  end
end

require_within Foo::Bar, "date"

x = Foo::Bar::Date.today

Anyone want to implement find_require_file and test the idea?

--Greg