From: Lloyd Zusman <ljz@...>
Date: 2005-02-20T06:42:29+09:00
Subject: Dynamically loading and executing within a new module?

I'm not sure what would be the best way to accomplish the following in
ruby:

I'm writing a program that periodically looks for files in a certain
directory.  If it finds new ones, I want it to ...

1. Dynamically create a new module whose name is based somehow upon the
   name of the file.

2. Do a Kernel#load on the file within this newly created module.

3. Invoke a method called #init that is defined in this file (assuming
   that this method is actually defined), and do the invocation within
   the context of that newly-created module.

For example, suppose my directory contains the following files:

  foo.module
  ----------
  def init
    puts "invoking #init within #{self}"
  end

  bar.module
  ----------
  def init
    puts "invoking #init within #{self}"
  end

When my program encounters the "foo.module" file, I'd like it to do the
following:

  - create a module called Foo (the name of the file with ".module"
    stripped off and the first letter capitalized) ... or maybe
    SomethingElse::Foo, to avoid collisions with existing packages

  - do a load() of the "foo.module" file within the context of this
    newly created Foo module (or SomethingElse::Foo module)

  - check to see if the #init method is now defined within the
    Foo module; if so, invoke that as a class method within the
    context of that module (i.e., as if it were invoked like
    Foo#init); this should cause the following message to
    print:

      invoking #init within Foo

What is the recommended way for accomplishing all this within Ruby?

-- 
 Lloyd Zusman
 ljz@asfast.com
 God bless you.