nothrow by default

[Guillaume Piolat]

On Friday, 10 January 2020 at 03:42:53 UTC, Gregor Mückl wrote:
> The longer this discussion drags on, the more I doubt my 
> understanding of this topic.
>
> What exactly is the execution overhead for non-throwing code 
> paths?


My understanding is that there is no overhead for functions that 
transitively don't throw or catch.


It's also my experience that

     A. _the bottlnecksin a program are almost NEVER functions 
that throw_ so why optimize the other parts?

     B. Giving up a little bit of safety for performance ruins all 
potential gains because of the overhead of introducing more bugs. 
Fixing one such bug will negate whatever performance gain.

     C. If you do need performance AND errors (typically: parsing 
without ranges/exceptions vs parsing with error codes) then you 
can resort locally to error codes.

     D. Error codes makes very easy to forget them, misuse them, 
and makes code less readable. They make very easy to conflate 
unrecoverable errors and recoverable errors.


The current internet backlash against exceptions is really 
puzzling to me: it's a sort of _revisionism_ because in the 
trenches exceptions are holding things together so they don't 
break more horribly. It think these people don't know how worse 
it could be.