On 07/31/2014 09:19 PM, Walter Bright wrote:
On 7/31/2014 6:37 AM, Daniel Gibson wrote:
The behavior you desire here is easily handled by creating your own
template to exhibit it. See the implementation of enforce() for how to
do it.
Now that's a bit surprising to me, as you wrote in the other thread:
> 7. using enforce() to check for program bugs is utterly wrong.
> enforce() is a library creation, the core language does not recognize
> it."
Until now (being mostly a C/C++ guy), I saw assertions as a way to
find bugs
during development/testing that is completely eliminated in release
mode (so I
might still want to handle the asserted conditions gracefully there) -
and it
seems like I'm not alone with that view.
The assert will not cause code to be generated to test the assertion at
runtime with -release. But the assert must still be valid, and since it
is valid, the optimizer should be able to take advantage of it.
assert is not meant to be used as "I want my program to be valid even if
the assert is false".
...
An assert does not have any bearing on program validity if assertions
are disabled.
Because (in C/C++) assertions just vanish when NDEBUG isn't defined,
it would
never occur to me that they have any influence on such (release mode)
builds.
Doing optimizations on this would just lead to frustration, like
several kinds
of optimizations recently have (e.g. this "compiler will remove
bzero() on
memory that isn't used afterwards" bullshit).
That's the way assert in C/C++ conventionally worked.
Right. Note 'conventionally' as in 'convention'. Why break the convention?
But this is
changing. Bearophile's reference made it clear that Microsoft C++ 2013
has already changed,
No way, their assert macro conforms to the standard.
http://msdn.microsoft.com/en-us/library/9sb57dw4.aspx
and I've seen discussions for doing the same with gcc and clang.
...
And I've seen discussions for introducing silent breaking changes into
D. It usually didn't happen. Why are those discussions deemed to be
_more relevant than the standard_ in the first place?
In fact, the whole reason assert is a core language feature rather than
a library notion is I was anticipating making use of assert for
optimization hints.
I was under the impression it was because of assert(0).
