bachelor.logic

国外的一套开源CRM

/*
This demonstrates the comparison, and mostly negation.
Try the query:
    bachelor(B)
which should produce the result:
    B = dirk
    no more results
*/
bachelor(X) :- 
    male(X), oldEnough(X), not married(X);

oldEnough(Person) :- 
    age(Person, Age), >=(Age, 18);

married("steve");

age("steve", 29);
age("dirk", 25);
age("frank", 9);

male("steve");
male("dirk"); 
male("frank");