From: Chad Perrin <code@...>
Date: 2011-11-12T07:04:15+09:00
Subject: Re: referring to version numbers in a gem

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On Sat, Nov 12, 2011 at 05:28:15AM +0900, Chad Perrin wrote:
> How do I specify and access a gem's version number within the code of the
> gem itself?  For example:
>=20
> 1. I write a library.
> 2. I write a command line utility that uses that library.
> 3. The utility uses OptionParser, with a --version option.
> 4. I package the things up inside a gem.
>=20
> What's the best way to specify the version number and give the code
> executed when the --version argument is supplied the ability to access
> that version number?

For now, I'm going with the following.

lib/gem_name.rb:

    module GemName
      @version =3D Gem::Version.new 'N.N.N'
      def self.version; @version; end
     =20
      . . .
    end

gem_name.gemspec:

    load 'lib/gem_name.rb'
   =20
    Gem::Specification.new do |s|
      s.version =3D GemName.version.to_s
      . . .
    end

bin/gemname:

    #!/usr/bin/env ruby
    require 'gem_name'
    require 'optparse'
   =20
    . . .
   =20
    opts =3D OptionParser.new do |opts|
      . . .
     =20
      opts.on_tail('--version', help_text[:version]) do
        puts "#{0} #{GemName.version} . . ."
      end
    end

If anyone sees any problems with that approach, I'd like to hear about
it, but it seems to be working well enough for the moment.

--=20
Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ]

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