class VersionInfo include Comparable attr_reader :major, :minor, :patch def self.parse(str) if str && m = str.match(/(\d+)\.(\d+)\.(\d+)/) VersionInfo.new(m[1].to_i, m[2].to_i, m[3].to_i) else VersionInfo.new end end def initialize(major = 0, minor = 0, patch = 0) @major = major @minor = minor @patch = patch end def <=>(other) return unless other.is_a? VersionInfo return unless valid? && other.valid? if other.major < @major 1 elsif @major < other.major -1 elsif other.minor < @minor 1 elsif @minor < other.minor -1 elsif other.patch < @patch 1 elsif @patch < other.patch -1 else 0 end end def to_s if valid? "%d.%d.%d" % [@major, @minor, @patch] else "Unknown" end end def valid? @major >= 0 && @minor >= 0 && @patch >= 0 && @major + @minor + @patch > 0 end end