The Right Approach to Exceptions

[Andrei Alexandrescu]

On 2/19/12 5:28 PM, Jonathan M Davis wrote:
> On Sunday, February 19, 2012 18:48:02 address_is at invalid.invalid wrote:
>> I guess "transient" is more descriptive.
>
> Actually, thinking on it some more, I don't think that transient will work at
> all, and the reason is simple. _Which_ operation should you retry?

The application decides.

> You don't
> even necessarily know which function the exception came from out of the
> functions that you called within the try block - let alone which function
> actually threw the exception. Maybe it was thrown 3 functions deep from the
> function that you called, and while retrying that specific call 3 functions
> down might have made sense, retrying the function 3 functions up doesn't
> necessarily make sense at all.
>
> Whether or not you can retry or retrying makes any sense at all is _highly_
> dependent on who actually catches the exception. In many cases, it may be a
> function which could retry it, but in many it won't be, and so having the
> exception tell the caller that it could retry would just be misleading.

No dependence on context. The bit simply tells you "operation has 
failed, but due to a transitory matter". That is information local to 
the thrower.


Andrei