From: Intransition <transfire@...>
Date: 2011-10-08T23:22:49+09:00
Subject: Re: don't understand -r



On Oct 8, 5:24 am, Brian Candler <b.cand...@pobox.com> wrote:
> Thomas Sawyer wrote in post #1025570:
>
> > btw, my original usecase, that led me this, was an attempt to run
> > minitest-based tests through a custom report format.
>
> >     $ ruby -r'minitest/tapy' test/test-*.rb
>
> And the problem is that this doesn't work because rubygems isn't
> installed, or something else?
>
> For me, -r works with rubygems in 1.9.2:
>
> $ sudo gem192 install haml
> Successfully installed haml-3.1.3
> ...
> $ ruby192 -rhaml -e 'p Haml.constants'
> [:ROOT_DIR, :Util, :Version, :VERSION, :Helpers, :Buffer, :Shared,
> :Parser, :Compiler, :Filters, :Error, :SyntaxError, :Engine]
>
> $ ruby192 -v
> ruby 1.9.2p0 (2010-08-18 revision 29036) [x86_64-linux]

Yes, I have been informed that with 1.9.x, rubygems is always loaded
so RUBYOPT="-rubygems" is no longer even needed. That fixes the issue
for loading from gems. It remains however a limitation for any custom
load manager, like the one I use.

A simpler example of the limitation would be load monitor --overriding
require to log everything request.

  $ cat req.rb
  puts "Custom Require"

  module Kernel
    alias :require0 :require

    def require(*a)
      puts "Kernel#require"
      p a
      require0(*a)
    end

    class << self
      alias :require0 :require

      def require(*a)
        puts "Kernel.require"
        p a
        require0(*a)
      end
    end
  end

Now if we do:

  $ export RUBYOPT="-rreq.rb"

Then the difference between:

  ruby -rhaml -e'p Haml.constants'

and

  ruby -e'require "haml"; p Haml.constants'

is apparent.