starredshort.logic

国外的一套开源CRM

/*
This is a very simple example of a fact query.
Try the following query:
    starred("James Cagney", Title, Year)
or for something a little more fun:
    starred("James Cagney", Title, Year), >(Year, 1950)
which should produce the following result:
    Title = Mister Roberts, Year = 1955.0
    Title = Ragtime, Year = 1981.0
    no more results
or for the same fun thing put inside a rule:
    starredAfter("James Cagney", title, year, 1950)
which should produce the following result (same as above except different var names):
    title = Mister Roberts, year = 1955.0
    title = Ragtime, year = 1981.0
    no more results
*/

starred("James Cagney", "Mutiny on the Bounty", 1935);
starred("James Cagney", "Yankee Doodle Dandy", 1942);
starred("James Cagney", "Mister Roberts", 1955);
starred("James Cagney", "Ragtime", 1981);

starredAfter(actor, title, year, afterYear) :-
    starred(actor, title, year), >(year, afterYear);