Exception handling

Raising and catching

In the following an exception of type E is thrown an then catched.

E = object()

try
  raise table E{value = "Some message"}
catch e if e: E
  print(e.value)
end

The catch-part is only reached if the exception is of type E. It can also be stated by means of an unconditional catch.

try
  raise table E{value = "Some message"}
catch e
  if e: E
    print(e.value)
  else
    raise e
  end
end

But in case of an unconditional catch, the traceback so far will be clipped off.