calrom formatter summarizing the day's liturgy in just one or two characters

ultra_condensed_formatter.rb

# custom formatter for calrom https://github.com/calendarium-romanum/calrom

# Don't expect calrom code to be already loaded, load all direct dependencies of our class - this allows usage like
# $ RUBYOPT="-I my/custom/code/dir -r ultra_condensed_formatter" calrom -f ultracondensed --today
require 'calrom/formatter/formatter'

module Calrom
  module Formatter
    # Prints just one or two characters signalling
    # what kind of celebration is celebrated today.
    # ("Is it a regular ferial/Sunday, or should I look in the
    # detailed calendar?")
    # Intended for use in WM panels on small displays.
    class Ultracondensed < Formatter
      def call(calendar, date_range)
        calendar.each_day_in_range(date_range) {|d| day_rank d }
      end

      private

      def day_rank(liturgical_day)
        c = liturgical_day.celebrations.first
        rank = c.rank

        r =
          if rank.solemnity?
            'S'
          elsif rank.feast?
            'F'
          elsif rank.sunday?
            'D'
          elsif rank.memorial?
            'm'
          elsif rank.ferial?
            'f' + (liturgical_day.celebrations.size > 1 ? '+' : '')
          else
            raise "unexpected rank #{rank.inspect}"
          end

        puts r
      end
    end
  end
end