Logic programming

gistfile1.txt

use hyperon::metta::*;
use hyperon::metta::interpreter::*;

fn main() {
    let space = metta_space("
        (= (if True $a) $a)
        (= (if False $a) nop)
        (= (and True True) True)
        (= (and True False) False)
        (= (and False True) False)
        (= (and False False) False)
        
        (= (male herbert) True)
        (= (male christa) False)
        (= (parent patrick herbert) True)
        (= (parent patrick christa) True)
        (= (father $1 $2) (and (parent $1 $2) (male $2)))
        (= (son $1 $2) (father $2 $1))

    ");
   println!("{:?}", interpret(&space, &metta_atom("(if (son herbert $1) (print $1))")));
}