Blog post example for truth tables

truth_example.rb

# defining some constants
ARCHIVE_REQUESTED       = 1 # binary 01
ARCHIVE_NOT_REQUESTED   = 0 # binary 00

FINISHED_PROCESSING     = 2 # binary 10
NOT_FINISHED_PROCESSING = 0 # binary 00

NOOP                    = 0 # binary 00
START                   = 1 # binary 01
BROKEN                  = 2 # binary 10
FINISHED                = 3 # binary 11

def archive_requested?
   if user.requested_archive == true
     ARCHIVE_REQUESTED
   else
     ARCHIVE_NOT_REQUESTED
   end
end

def finished_processing?(user_id)
  if archiver.processing_state(user_id) == :finished
    FINISHED_PROCESSING
  else
    NOT_FINISHED_PROCESSING
  end
end

def archive_state(user)
  result = archive_requested? | finished_processing?(user.id)
  
  case result
    when NOOP                then nil
    when START               then archiver.start_processing(user.id)
    when FINISHED            then archiver.get_file(user.id)
    when BROKEN              then notify_engineers
  end
end