Formatting -0.0 as 0.0
Bastiaan at Veelo.net
Fri Oct 15 15:18:45 UTC 2021
Thank you Steve.
On Friday, 15 October 2021 at 14:09:32 UTC, Steven Schveighoffer
> On 10/15/21 8:37 AM, Bastiaan Veelo wrote:
>> What I would like best is if there were a format specifier
>> flag that does this conversion automatically, like "%> 4.3f".
>> Does it make sense to add this? Is there a better way?
> The only way I can think of that isn't really intrusive (like
> your `posZero` thing) is to define your own `writef`/`format`
> wrappers (what I'd do is check any doubles, and replace them
> when necessary).
The thing that is holding me back is that it feels backwards to
wrap `std` to fix what I perceive as a usability issue, contra
fixing `std` itself. Hence my proposal of extending the format
specification -- although I find it complicated enough as it is.
I am surprised that I am the first to have this problem.
I think I'm going to follow your suggestion nonetheless, as
seeing `posZero` all over the place looks ridiculous...
> Another thing to do is to catch it at the source. That is, when
> you store a value somewhere where it might be printed, if it's
> `-0.0`, change it to `0.0`.
Is not an option in my situation, as it must work on machine
translated code. For new code it would work, but I doubt our
programmers will be conscious of the issue at all times. As we
work with a left-handed coordinate system, multiplying Y with -1
happens frequently, and 0 is a common value for Y. Easy to miss a
> Note that if ldc is optimizing out an addition with 0, and that
> actually changes the observable results, that technically is an
> invalid optimization.
Issue filed: https://github.com/ldc-developers/ldc/issues/3851
Fun fact: I checked two other Pascal compilers: gpc prints `-0.0`
as `0.0` like our old compiler does, fpc is like D and prints it
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