# File lib/locale/tag/posix.rb, line 32
      def self.parse(tag)
        if tag =~ /^(C|POSIX)$/
          ret = self.new("en", "US")
          ret.tag = tag
          ret
        elsif tag =~ TAG_RE
          ret = self.new($1, $2, $3, $4)
          ret.tag = tag
          ret
        else
          nil
        end
      end