         }
     }
 } catch {
+    // Quit
     print("")
 }

    fatalError("Invalid filename")
}

do {
    while true {
        print("? ", terminator: "")
        guard let line = InputStream().getLine() else { throw InputError.EndOfFile }
        do {
            let q = try terminating(query).parse(line.characters)
            
            let success = system.query(q) { results in
                if results.isEmpty {
                    print("True")

    case EndOfFile
}

// Parse input
guard Process.arguments.count == 2 else {
    fatalError("usage: \(Process.arguments[0]) [filename]")
}
let filename = Process.arguments[1]

// Load file
let system: Logic
if let file = FileStream(filename) {
    do {
