50 lines
1.7 KiB
Haskell

module Main where
import Database
import Nondeterminism
import Classes
import Terms
import Binding
demoProgram :: Database
demoProgram = Database
{ clauses =
-- act(sam, 'goes to law school')
[ return $ Clause (Compound "act" [Compound "Sam" [], Compound "goes to law school" []]) []
, return $ Clause (Compound "vampire_behavior" [Compound "drinks blood" []]) []
, return $ Clause (Compound "vampire_behavior" [Compound "spits venom" []]) []
, do
-- act(Who, Action) :- is_vampire(Who), vampire_behavior(Action).
who <- newVar "Who"
action <- newVar "Action"
return $ Clause (Compound "act" [Var who, Var action])
[ Compound "is_vampire" [Var who]
, Compound "vampire_behavior" [Var action]
]
, do
-- is_vampire(Progeny) :- has_progenitor(Progenitor, Progeny), is_vampire(Progenitor)>
progenitor <- newVar "Progenitor"
progeny <- newVar "Progeny"
return $ Clause (Compound "is_vampire" [Var progeny])
[ Compound "has_progenitor" [Var progenitor, Var progeny]
, Compound "is_vampire" [Var progenitor]
]
, return $ Clause (Compound "is_vampire" [Compound "Nyeogmi" []]) []
, return $ Clause (Compound "has_progenitor" [Compound "Sam" [], Compound "Alex" []]) []
, return $ Clause (Compound "is_vampire" [Compound "Sam" []]) []
]
}
main :: IO ()
main = do
thread <- newThread runDemoProgram
_ <- takeAllRemainingSolutions thread
return ()
where
runDemoProgram :: PrologStream ()
runDemoProgram = do
who <- newVar "who"
what <- newVar "what"
let goal = Compound "act" [Var who, Var what]
goal' <- seekAndInstantiate goal demoProgram
liftIO $ putStrLn ("Got " ++ show goal')