Welcome to DrScheme, version 209.
Language: Textual (MzScheme, includes R5RS).
> factbase
((loves john mary)
 (rich katy)
 (rich jane)
 (near katy mall)
 (near jane landfill)
 (man tim)
 (man hank)
 (food quiche)
 (hungry hank)
 (hungry katy)
 ((loves ?x130 ?y131) :- (man ?x130) (woman ?y131))
 ((woman ?z129) :- (likes ?z129 shopping) (eats ?z129 quiche))
 ((likes ?x128 shopping) :- (rich ?x128) (near ?x128 mall))
 ((eats ?x126 ?y127) :- (hungry ?x126) (food ?y127)))
> (prove '(woman jane))
"fail"
> (prove '(woman katy))
()
> (prove '(woman ?x))
((?x katy))
> (prove '(loves ?x y))
"fail"
> (prove '(loves ?x ?t))
((?t mary) (?x john))
> (prove '(loves ?x katy))
((?x tim))
> (prove '(loves hank ?e))
((?e katy))
> (prove '(loves tim ?x))
((?x katy))
> (prove '((near jane ?x) (eats ?y ?u)))
((?x landfill) (?y hank) (?u quiche))
> (prove '((eats ?x quiche) (loves ?x katy)))
((?x hank))
>