datatype peano = Z | S of peano
datatype plist = nilpl | consp of peano * plist
 
fun f( InVal : plist ) : peano = raise D1
fun main( Xs : plist ) : peano = f Xs

%%

fun to_plist [] = nilpl
  | to_plist( X :: Xs ) = consp( X, to_plist Xs )

val Input = [
  ( [] ),
  ( [Z] ),
  ( [Z,S(Z)] ),
  ( [S(Z),S(Z)] ),
  ( [S(Z),S(S(Z))] ),
  ( [S(Z),S(S(Z)),Z] ),
  ( [S(Z),S(S(Z)),S(Z)] ),
  ( [S(Z),S(S(Z)),S(S(Z))] ),
  ( [S(S(S(Z))),S(S(Z)),S(Z)] )
]

val Inputs = map( to_plist , Input )

val Outputs = [
  ( Z ),
  ( Z ),
  ( S(Z) ),
  ( S(S(Z)) ),
  ( S(S(S(Z))) ),
  ( S(S(S(Z))) ),
  ( S(S(S(S(Z)))) ),
  ( S(S(S(S(S(Z))))) ),
  ( S(S(S(S(S(S(Z)))))) )
  ]

val Validation_inputs = []
val Validation_outputs = []

val All_outputs =  Vector.fromList( Outputs @ Validation_outputs )
 
val Funs_to_use = [ "S", "Z", "nilpl", "consp", "true", "false" ]
 
val Reject_funs = []
fun restore_transform D = D
 
structure Grade : GRADE =
struct
 
type grade = unit
val zero = ()
val op+ = fn(_,_) => ()
val comparisons = [ fn _ => EQUAL ]
val toString = fn _ => ""
val fromString = fn _ => SOME()
 
val pack = fn _ => ""
val unpack = fn _ =>()
 
val post_process = fn _ => ()

val toRealOpt = NONE
 
end
 
val Abstract_types = []
 
fun output_eval_fun( I : int, _ , Y ) =
  if Vector.sub( All_outputs, I ) <> Y then
    { numCorrect = 0, numWrong = 1, grade = () }
  else
    { numCorrect = 1, numWrong = 0, grade = () }
 
 
val Max_output_class_card = 2
val Max_output_genus_card = 0
val Max_time_limit = 131072
val Time_limit_base = 2.0