!752

sS data = [=[
  [[house] is a noun_clause]
  [if [[X] is a noun_clause] then [[my X] is a noun_clause]]
  [[my house] is a noun_clause]
]=];

p {
  // make Prolog interpreter
  new Prolog p;
  p.upperCaseVariables = true;
  //p.showStuff = true;
  p.addTheory(dropLastLine(rtrim(data)), programID());
  Lisp pivot = nlParse(lastLine(rtrim(data)));
  
  // derive third rule from first two
  L<Lisp> l = p.rewrite(100);
  print("Found " + nl(l, "statement") + ":");
  //printIndent(snlAllToText(l));
  printIndent(nlUnparseLines(l));
  print();
  print("Pivot statement: " + nlUnparse(pivot));
  int idx = l.indexOf(pivot);
  print("Pivot statement found? " + 
    (idx >= 0 ? "Yes, at index " + (idx+1) + "/" + l(l) + "." : "No."));
}