On 10/17/2014 9:13 AM, Jacob Carlborg wrote:
On 2014-10-16 21:31, Walter Bright wrote:
Contract errors in Phobos/Druntime should be limited to having passed it
invalid arguments, which should be documented
That doesn't mean it won't happen.
Which means they'll be program bugs, not environmental errors.
It is of great value to distinguish between program bugs and input/environmental
errors, and to treat them entirely differently. It makes code easier to
understand, more robust, and better/faster code can be generated.
Using asserts to detect input/environmental errors is a bad practice - something
like enforce() should be used instead.
I understand that some have to work with poorly written libraries that
incorrectly use assert. If that's the only issue with those libraries, you're
probably lucky :-) Short term, I suggest editing the code of those libraries,
and pressuring the authors of them. Longer term, we need to establish a culture
of using assert/enforce correctly.
This is not as pie-in-the-sky as it sounds. Over the years, a lot of formerly
popular bad practices in C and C++ have been relentlessly driven out of
existence by getting the influential members of the communities to endorse and
advocate proper best practices.
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I do my best to practice what I preach. In the DMD source code, an assert
tripping always, by definition, means it's a compiler bug. It is never used to
signal errors in code being compiled or environmental errors. If a badly formed
.d file causes dmd to assert, it is always a BUG in dmd.
