// readFile reads the source of an entire project into a string, so this is like a C-style include
eval(readFile("Prolog_Library"))

ometa PrologTranslator {
  variable = spaces firstAndRest(`upper, `letterOrDigit):name  -> new Var(name.join('')),
  symbol   = spaces firstAndRest(`lower, `letterOrDigit):name  -> new Sym(name.join('')),
  clause   = symbol:sym "(" listOf(`expr, ','):args ")"        -> new Clause(sym, args),
  expr     = clause | variable | symbol,
  clauses  = listOf(#clause, ','),
  rule     = clause:head ":-" clauses:body      "."            -> new Rule(head, body)
           | clause:head                        "."            -> new Rule(head, []),
  prog     = (rule:r &clause -> r)*:rs clause:q "." spaces end -> {rules: rs, query: q}
}
translateCode = function(x) {
  var prog = PrologTranslator.matchAll(x, "prog")
  solve(prog.query, prog.rules)
}

// press 'Cancel' to see more solutions, and 'OK' if you've seen enough
nat(z).
nat(s(X)) :- nat(X).
nat(X).

father(abe, homer).
father(homer, lisa).
father(homer, bart).
father(homer, maggie).
grandfather(X, Y) :- father(X, Z), father(Z, Y).
grandfather(X, Y).