IMPLEMENTATION Person

IMPORT Nat COMPLETELY
IMPORT Denotation COMPLETELY

DATA date == date(day   : nat,
                  month : nat,
                  year  : nat)

DATA person == person(name      : denotation,
                      surname   : denotation,
                      birthdate : date)

/* Aufg. 2.3. Induzierte Signatur:

   K: FUN person : denotation**denotation**date -> person
   D: FUN person? : person -> bool
   S: FUN name surname : person -> denotation
      FUN birthdate : person -> date

*/

FUN earlier? : date**date -> bool
DEF earlier?(date(a,b,c),date(d,e,f)) == IF c<f THEN true
                                                ELSE IF (c=f) and (b<e) THEN true
                                                ELSE IF (c=f) and (b=e) and (a<d) THEN true
                                                ELSE false
                                                FI
                                                FI
                                         FI

FUN older? : person**person -> bool
DEF older?(person(_,_,a),person(_,_,b)) == IF earlier?(b,a) THEN true ELSE false FI

FUN birthday : person -> nat**nat
DEF birthday(person(_,_,date(a,b,_))) == (a,b)

FUN sameName? : person**person -> bool
DEF sameName?(person(_,a,_),person(_,b,_)) == IF a=b THEN true ELSE false FI