wert310/rustpro

A slow Prolog implementation in Rust

RustPro

A slow Prolog implementation in Rust

Usage

To start the interpreter you need to run

$ cargo run <file>

where file is a prolog file.

A fact is entered by ending the clause with a dot:

?- lt(zero, succ(zero)).
ok.

A query is specified with a question mark:

?- member(2, cons(1, cons(2, cons(3, nil))))?
yes.

Examples

Zebra puzzle

$ rustpro example/zebra.pro
member(X, cons(X, _)).
member(X, cons(_, Zs)) :- member(X, Zs).
rightOf(X, Y, cons(X, cons(Y, _))).
rightOf(X, Y, cons(_, Zs)) :- rightOf(X, Y, Zs).
nextTo(X, Y, Z) :- rightOf(X, Y, Z).
nextTo(X, Y, Z) :- rightOf(Y, X, Z).
unify(X, X).
zebra(W, Z) :- 
  unify(Hs, cons(house(norwegian, _, _, _, _), cons(_, cons(house(_, _, _, milk, _), cons(_, cons(_, nil)))))),
  member(house(englishman, _, _, _, red), Hs), 
  member(house(spaniard, dog, _, _, _), Hs), 
  member(house(_, _, _, coffee, green), Hs), 
  member(house(ukranian, _, _, tea, _), Hs), 
  rightOf(house(_, _, _, _, green), house(_, _, _, _, ivory), Hs), 
  member(house(_, snails, oldgold, _, _), Hs), 
  member(house(_, _, kools, _, yellow), Hs), 
  nextTo(house(_, _, chesterfields, _, _), house(_, fox, _, _, _), Hs), 
  nextTo(house(_, _, kools, _, _), house(_, horse, _, _, _), Hs), 
  member(house(_, _, lukystrike, juice, _), Hs), 
  member(house(japanese, _, parliament, _, _), Hs), 
  nextTo(house(norwegian, _, _, _, _), house(_, _, _, _, blue), Hs), 
  member(house(Z, zebra, _, _, _), Hs), 
  member(house(W, _, _, water, _), Hs).
?- zebra(W,Z)?
W = norwegian, Z = japanese.
?-