From: Dave Burt <dave@...>
Date: 2005-09-09T18:26:30+09:00
Subject: Re: 'which' command for Ruby (like csh which?)

Dan Bikle asked:
> suppose I have,
>
> require "redgreenblue"
> in
> runme.rb
>
> Is there a way I can tell which
> redgreenblue.rb file will get pulled in to runme.rb
> at run time?

I don't know of anything built in, but this should do the trick:

def which(lib)
  lib += ".rb" unless lib[-3..-1] == ".rb"
  $LOAD_PATH.each do |path|
    file = File.join(path, lib)
    return file if FileTest.exist?(file)
  end
  if defined? Gem
    @gempath_searcher ||= Gem::GemPathSearcher.new
    if spec = @gempath_searcher.find(lib) and lib = spec.autorequire
      lib += ".rb" unless lib[-3..-1] == ".rb"
      spec.require_paths.each do |path|
        file = File.join(spec.full_gem_path, path, lib)
        return file if FileTest.exist?(file)
      end
    end
  end
  nil
end

Cheers,
Dave