document timeout

[prule]

Small change to add a note about how to control how long a jsonata expression can run and control max recursion. It wasn't obvious to me at first and I only found it by browsing the code/tests.

Seems like a pretty important thing any user of the library would want to know to prevent problems.

Feel free to ignore if you don't think its useful.

Thanks for the great library!

[aeberhart]

Thanks for the documentation. @uw4, do we want to keep the depth check? Seems like it only counts up when $eval is called:

  @Test
  public void timeoutTest() {
    var expr = jsonata("[0..9999999].{'x':1}");
    var frame = expr.createFrame();
    frame.setRuntimeBounds(1, 100);
    Assertions.assertThrows(JException.class, () -> expr.evaluate(null, frame));
  }

  @Test
  public void recursionTest() {
    var expr = jsonata("$eval('1' & $eval('1' & $eval('1')))");
    var frame = expr.createFrame();
    frame.setRuntimeBounds(100000, 2);
    Assertions.assertThrows(JException.class, () -> expr.evaluate(null, frame));
  }