From: Lars Olsson <lasso@...>
Date: 2010-08-17T02:20:16+09:00
Subject: Re: Determining whether the running ruby is outdated?

On 11 Aug, 21:35, Luis Lavena <luislav...@gmail.com> wrote:
> On Aug 11, 4:29 pm, Dan Rathbun <danzoi...@gmail.com> wrote:
>
> > Lars, I found where the information is in each package.
>
> > It is in the version.h file (a C source header file.)
>
> > In the some of the older precompiled packages, a copy of this file, is
> > placed in the #{platform} subdir of the ruby/lib/ruby/#{engine}
> > directory.
> > In newer precompiled packages, it cannot find it and it may have been
> > replaced with rbconfig.rb
>
> No, all versions of MRI (Matz Ruby Implementation) still stores
> version information in a C header, not Ruby code.
>
> > In the source packages, the file is in the source/#{ver-patchlevel} dir
> > of the source archives.
> > The problem with them is thay are all in compressed archives (tarballs
> > or zips,) so you cannot read them over the net.
>
> Yes, the only workaround is download, extract and find the file.
>
> In RubyInstaller we know what we are looking for:
>
> http://github.com/oneclick/rubyinstaller/blob/master/recipes/packager...http://github.com/oneclick/rubyinstaller/blob/master/recipes/packager...
>
> Do a Dir.glob and look for version.h
>
> --
> Luis Lavena

Thanks everybody for all of your suggestions. I finally decided that
the downloads available from ftp.ruby-lang.org provide me with the
information I need. Even though the information obtained cannot be
guaranteed to be accurate, the naming scheme on that site seems quite
stable.

If someone is interested the app is available on github:
http://github.com/lasso/random/raw/master/runtimeinfo.rb

And here are the results from my current irb session:

irb(main):001:0> load 'runtimeinfo.rb'
=> true
irb(main):002:0> puts
Lassoweb::Utils::RuntimeInfo.latest_ruby_versions
Latest stable version: 1.9.1-p430
Latest release candidate: 1.9.2-rc2
Latest preview: 1.9.2-preview3
=> nil

/lasso