DayRange

class DayRange SHORT_NAMES = %w[Mon Tue Wed Thu Fri Sat Sun].freeze LONG_NAMES = %w[ Monday Tuesday Wednesday Thursday Friday Saturday Sunday ].freeze def initialize(*days) @days = days.map do |d| ds = d.to_s.downcase.capitalize SHORT_NAMES.index(ds) || LONG_NAMES.index(ds) || d - 1 end rescue raise(ArgumentError, "Unrecognized number format.") unless @days.all? { |d| d.between?(0, 6) } raise ArgumentError, "Days must be between 1 and 7." end raise ArgumentError, "Duplicate days given." unless @days == @days.uniq end def to_s(names = SHORT_NAMES) raise ArgumentError, "Please pass seven day names." unless names.size == 7 @days.inject(Array.new) do |groups, day| if groups.empty? or groups.last.last.succ != day groups << [day] else groups.last << day groups end end.map { |g| g.size > 2 ? "#{g.first}-#{g.last}" : g.join(", ") }. join(", ").gsub(/\d/) { |i| names[i.to_i] } end end