-- Sergio Antoy, Fri Oct 20 22:01:56 PDT 2006
-- example of non-deterministic programming
-- find a donor for a blood transfusion to a patient
-- Updated by Michael and Sergio on Fri Mar  4 08:43:51 PST 2011
-- updated Wed Jul  5 19:52:44 PDT 2017

-- import List
import SetFunctions

import Test.EasyCheck
-- execute with: curry check blood

data BloodTypes = Ap | An | ABp | ABn | Op | On | Bp | Bn

give_to Ap  = Ap ? ABp
give_to Op  = Op ? Ap ? Bp ? ABp
give_to Bp  = Bp ? ABp
give_to ABp = ABp
give_to An  = Ap ? An ? ABp ? ABn
give_to On  = Ap ? An ? ABp ? ABn ? Op ? On ? Bp ? Bn
give_to Bn  = Bp ? Bn ? ABp ? ABn
give_to ABn = ABp ? ABn

receive_from (give_to x) = x

give_to'set x = set1 give_to x
receive_from'set x = set1 receive_from x

has "John" = ABp
has "Doug" = ABn
has "Lisa" = An

donorTo x
   | give_to (has y) == has x && x /= y
   = y
   where y free

receipientFrom x
   | receive_from (has y) == has x & x /= y
   = y
   where y free

allDonorTo x = sortValues (set1 donorTo x)
allReceipientFrom x = sortValues (set1 receipientFrom x)

people = [ "John", "Doug", "Lisa" ]

test1 = zip people (map allDonorTo people)
        -=- [("John",["Doug","Lisa"]),("Doug",["Lisa"]),("Lisa",[])]
test2 = zip (map allReceipientFrom people) people
        -=- [([],"John"),(["John"],"Doug"),(["Doug","John"],"Lisa")]