From: John Gabriele <jmg3000@...>
Date: 2006-06-16T03:40:20+09:00
Subject: Re: running applications installed from gems

On 6/15/06, Austin Ziegler <halostatue@gmail.com> wrote:
> [snip]
> The one in /opt/ruby-1.8.4/bin is the RubyGems stub. That's in your
> $PATH, because that's where your ruby executable is. The one in
> ...gems/pdf-writer-1.1.3/bin/techbook is my actual executable. The
> RubyGems stub will activate the PDF::Writer 1.1.3 gem (actually, the
> latest unless you select a specific version) and then "run" the one in
> the gems/... path, which is *not* in your $PATH.

Ah... I see. Thanks Austin. I'd forgotten that RubyGems allows
multiple versions of the same gem to be installed. But since the
exectuable stub is in a common directory, there's gotta be some way
for *it* to decide which version of the given gem to actually run.

So, I guess the convention then -- for when you want to supply an
executable with a gem -- is to tell the GemSpec you want a stub which
calls "load 'foo'". When that foo file is loaded, your app should run.
In the case of pdf-writer, both the stub and the module you load to
actually run the program happen to have the same name.

Further, I see that both
.../lib/ruby/gems/1.8/gems/pdf-writer-1.1.3/bin and
.../lib/ruby/gems/1.8/gems/pdf-writer-1.1.3/lib directories are in $:
when that "load 'techbook'" call is made from the stub.

Chapter 7 of the RubyGems user's guide
(http://docs.rubygems.org/read/chapter/5) doesn't have much, but
refers the reader to the DeveloperGuide, but I don't see a link to
that on the main RubyGems page.

I hopped over to my .../lib/ruby/site_ruby/1.8 directory, ran rdoc,
and had a look in the resulting lovely html, but didn't see a dev
guide in there either. Where can I find this developer's guide?