Question

I’ve been looking at the source code of a few gems lately. One idiom that I keep seeing is the use of a nested module containing version constants that are joined into a version string i.e. variations around this sort of thing:

module ChunkyBacon
  module Version
    MAJOR = 0
    MINOR = 6
    TINY  = 2
  end

  VERSION = [Version::MAJOR, Version::MINOR, Version::TINY].compact * '.'
end

What’s the advantage (if any) of storing the library version information in this way? Why not just do:

module ChunkyBacon
  VERSION = '0.6.2'.freeze
end

Answer 1

For programmatic compatibility checks, it’s easier to have an explicitly separated version number.

e.g.:

require 'chunkybacon'
if ChunkyBacon::VERSION::MAJOR > 0
  # barf
end