art.logic

国外的一套开源CRM

/*
This demonstrates the evaluation feature, among other things.
Try the query:
    painterAge("seurat", title, age)
which should produce the result:
    title = Bathers at Asni鑢es, age = 25.0
    title = Sunday Afternoon, age = 27.0
    title = The Models, age = 29.0
    no more results
*/

// facts from an art database
painting("Bathers at Asni鑢es", "seurat", 1884);
painting("Sunday Afternoon", "seurat", 1886);
painting("The Models", "seurat", 1888);
//...
artist("cezanne", "paul", 1839);
artist("gauguin", "paul", 1848);
artist("seurat", "georges", 1859);
//...

painterAge(Artist, Title, Age) :-
    artist(Artist, First, Born),
    painting(Title, Artist, Year),
    #(Age, Year - Born);