[eeereerews]

But once you've accepted unchecked exceptions (and paid the cost of the having them), it just doesn't make sense to only use them only for bugs. For example, it is better to

  try:
    x = json['foo']['bar'][i]
  catch OOB:
    handle error

than to

  if not (json is a dict and
          'foo' in json and
          json['foo'] is a dict and
          ...):
    handle error
  x = json['foo']['bar'][i]

even though in the former, unchecked exceptions are used for non-bugs.

[nicoburns]

The idea is that for bugs you don't even need a try-catch (or maybe one around your entire program). And pattern matching and functions like `map` make the second case much nicer.