From: Joel VanderWerf <vjoel@...>
Date: 2005-10-22T06:18:16+09:00
Subject: Re: Getting a file location and name...

Joe Van Dyk wrote:
> Hi,
> 
> Say I have /joe/configuration/config.rb:
> ==============================
> puts "this configuration file is located in this directory: " +
> File.dirname( ????? )
> eval File.read(File.dirname( ?????? ) + "/common.rb")
> # other stuff
> ==============================
> 
> common.rb is located in /joe/configuration.  It also contains some Ruby code.
> 
> 
> The main program looks something like this:
> ==============================
> config_file = ARGV.shift
> eval File.read config_file
> ==============================
> 
> And I'd start the program via 'ruby main.rb /joe/configuration.rb'.
> 
> So, I have a main program that reads in a Ruby configuration file that
> can also read other configuration files that are in a relative
> directory.  I'm having problems with the relative directory part.  If
> I hardcode the directory paths, everything's ok.  But I don't want
> /joe/configuration/config.rb to know that it's in /joe/configuration. 
> I just want that configuration file to be able to read
> /joe/configuration/common.rb.
> 
> Sorry if this is confusing, let me know if I can clarify the question.
> 
> Joe
> 

What about something like

def with_load_path(path)
  $LOAD_PATH.unshift path
  yield
ensure
  $LOAD_PATH.shift
end

Then use that around your #eval call in the main program, with the
'/joe/configuration' as the argument. Then require should work relative
to the path you gave. (But note that $LOADED_FEATURES will prevent files
with the same name from being loaded again, even if in a different
config dir.)

Not thread safe, but oh well.

Another option: my "script" lib (see RAA). That makes sure that the
global $LOADED_FEATURES doesn't get affected.

-- 
      vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407