-- 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

import List
import SetFunctions

infix 4 =/=

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

x =/= y = (x == y) =:= False

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 = set1 donorTo x
allReceipientFrom x = set1 receipientFrom x

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

test1 = map allDonorTo people
test2 = map allReceipientFrom people