assert semantic change proposal

[John Carter via Digitalmars-d]

On Sunday, 3 August 2014 at 20:05:22 UTC, bachmeier wrote:

>> 3. Undefined behavior.

Actually I have had an extensive battle within my own workplace 
on this subject and I think I have a reasonable insight in to 
both points of view.

It comes down to two opposing view of what we use asserts for.

My view, which I think corresponds with Walter's and Betrand 
Meyer's, is that asserts define what correct behaviour is.

If an assert fires, your program is fundamentally defective in a 
manner that can only be corrected by a new version of the program.

And the sooner you know that, preferably at compile time, the 
better.

Continuing past such an assert inevitably results in defective, 
possibly catastrophic, possibly flaky behaviour.

In the opposing view, an assert statement is a debug aid. In the 
same category as a logging printf.

If it fires, it's "Huh. That's interesting. I didn't think that 
would happen, but OK, it does. Cool."

Alas, these two uses have been given the same name. assert.

One resolution would be to create two assert interfaces, one that 
the compiler pays attention to, and one that is just a "Huh. 
That's interesting, I didn't expect that."