precode.txt

let contract = tx.sender
let a = extract(getInteger(contract,"human"))
let wolf= extract(getInteger(contract,"wolf"))
let golf= extract(getInteger(contract,"goat"))
let cabbage= extract(getInteger(contract,"cabbage"))

match tx {
case t:DataTransaction =>
   let newHuman = extract(getInteger(t.data,"human")) 
   let krot = extract(getInteger(t.data, "wolf"))
   let newGoat= extract(getInteger(t.data, "goat"))
   let newCabbage= extract(getInteger(t.data,"cabbage"))
   
   let humanSide= a == 0 || a == 1
   let wolfSide= wolf == 0 || wolf == 1
   let golfSide= golf == 0 || golf == 1
   let cabbageSide= cabbage == 0 || cabbage == 1
   let side= humanSide && wolfSide && golfSide && cabbageSide

   let safeAlone= newGoat != krot && newGoat != newCabbage
   let safe= safeAlone || newGoat == newHuman
   let humanTravel= a != newHuman 

   let t1= humanTravel && krot == wolf + 1 && newGoat == golf && newCabbage == cabbage 
   let t2= humanTravel && krot == wolf && newGoat == golf + 1 && newCabbage == cabbage
   let t3= humanTravel && krot == wolf && newGoat == golf && newCabbage == cabbage + 1
   let t4= humanTravel && krot == wolf - 1 && newGoat == golf && newCabbage == cabbage
   let t5= humanTravel && krot == wolf && newGoat == golf - 1 && newCabbage == cabbage
   let t6= humanTravel && krot == wolf && newGoat == golf && newCabbage == cabbage - 1
   let t7= humanTravel && krot == wolf && newGoat == golf && newCabbage == cabbage
   let objectTravel = t1 || t2 || t3 || t4 || t5 || t6 || t7
   
   side && safe && humanTravel && objectTravel
case s:TransferTransaction =>
   let first = a == 1 && wolf == 1
   let second = golf == 1 && cabbage == 1
   first && second

case _ => true

}