On Wednesday, 6 August 2014 at 22:31:00 UTC, Walter Bright wrote:
On 8/6/2014 5:14 AM, "Marc Schütz" <schue...@gmx.net>" wrote:
We're not living in an ideal world, unfortunately. It is bad
enough that
programs are wrong as they are written, we don't need the
compiler to transform
these programs to do something that is still wrong, but also
completely
different. This would make your goal of fixing the program
very hard to achieve.
In an extreme case, a small error in several million lines of
code could
manifest at a completely different place, because you cannot
rely on any
determinism once undefined behaviour is involved.
You are technically correct, and I used to worry about that.
But after using assert()s for 30 years, I can only think of
this happening once. assert()s tend to trip very shortly after
the actual error occurred. Of course, there's a bit of an art
to appropriate placement of those assert()s.
But for those 30 years you only used asserts with the semantics
they have in C, not with the semantics you want for D. I don't
see how you can come to the conclusion that the same is true for
the "new style" assertions.
The problems with finding errors that I talk about are not
because the cause of the error is far from the assert. They stem
from the fact that - with the proposed semantics - the asserts
themselves can influence code in different parts of the program,
far away from both the cause of the error and the failed assert.
