!752

static class Process {
  S name;
  int id;
  Thread thread;
  Runnable code;
  volatile long started, ended;
  volatile O result; // ?
  volatile Throwable error;
}

static new L<Process> processes;
static int idCounter;

synchronized answer {
  if "list processes" exceptionToUser {
    new L l;
    for (Process p : processes)
      // drop the problem fields
      l.add(dropKeys(litlist("thread", "code"), objectToMap(p)));
    ret slackSnippet(structureLines(l));
  }
  
  if "test process" {
    new Process p;
    p.name = "Test process (sleeps for 10)";
    p.code = runnable {
      sleepSeconds(10);
    };
    ret addProcess(p);
  }
}

static S addProcess(final Process p) {
  p.thread = new Thread() {
    public void run() {
      p.started = now();
      try {
        p.code.run();
      } catch (Throwable e) {
        p.error = e;
      }
      p.ended = now();
    }
  };
  p.id = ++idCounter;
  processes.add(p);
  p.thread.start();
  ret "Added & started, process id: " + p.id;
}

static synchronized Process start(S name, Runnable code) {
  new Process p;
  p.name = name;
  p.code = code;
  addProcess(p);
  ret p;
}