Re:Which language has the brightest future for replacing C: ...
by quotemstr on Wednesday November 11, 2015 @08:45AM
(#10546593)
> return exceptions to their roots by relegating them to exceptional circumstances
Python does it right. I've never bought the argument that "exceptions are for exceptional circumstances". If you use error codes for some errors and exceptions for others, all you do is confuse people. The definition of "exceptional error" is subjective, after all.
As far as I can tell, the advice to use "exceptions for exceptional circumstances" originated in C++ circles in the 1990s, when support for exceptions was bad and throws were slow. The thinking was that you could efficiently use error codes for commonly-encountered errors and still get some of the syntactic benefits of using exceptions for rarer errors. Also, if you were using a compiler without exceptions support, you could turn your exceptions into aborts while not aborting just because a file doesn't exist. You can see vestiges of this thinking in the iostreams API.
Somehow, this performance hack morphed into commonly-accepted dogma. I don't accept this dogma. Exceptions are for any situation that a function can't meet its contract. In Python, if an iterator can't supply its next element, it can't satisfy the contract, and the exception tells you why. I don't think there's anything particularly wrong with that.
Python does it right. I've never bought the argument that "exceptions are for exceptional circumstances". If you use error codes for some errors and exceptions for others, all you do is confuse people. The definition of "exceptional error" is subjective, after all.
As far as I can tell, the advice to use "exceptions for exceptional circumstances" originated in C++ circles in the 1990s, when support for exceptions was bad and throws were slow. The thinking was that you could efficiently use error codes for commonly-encountered errors and still get some of the syntactic benefits of using exceptions for rarer errors. Also, if you were using a compiler without exceptions support, you could turn your exceptions into aborts while not aborting just because a file doesn't exist. You can see vestiges of this thinking in the iostreams API.
Somehow, this performance hack morphed into commonly-accepted dogma. I don't accept this dogma. Exceptions are for any situation that a function can't meet its contract. In Python, if an iterator can't supply its next element, it can't satisfy the contract, and the exception tells you why. I don't think there's anything particularly wrong with that.