Program logic bugs vs input/environmental errors

[Walter Bright via Digitalmars-d]

On 10/18/2014 8:21 AM, Jacob Carlborg wrote:
> On 2014-10-18 07:09, Walter Bright wrote:
>
>> Which means they'll be program bugs, not environmental errors.
>
> Yes, but just because I made a mistake in using a function (hitting an assert)
> doesn't mean I want to have undefined behavior.


As I've said before, tripping an assert by definition means the program has 
entered an unknown state. I don't believe it is possible for any language to 
make guarantees beyond that point.

Now, if it is a "known" unknown state, and you want to recover, the solution is 
straightforward - use enforce(). enforce() offers the guarantees you're asking for.

Using assert() when you mean enforce() is like pulling the fire alarm but not 
wanting the fire dept. to show up.