Conditional compilation for non-release version

[bearophile]

Joseph Rushton Wakeling:

> Is there a way to put in place a conditional segment of code 
> that is included if the code is _not_ compiled with the 
> -release flag?

Contract programming? D is designed to make it hard on purpose to
do what you want to do.


> The reason I'm asking is because the checks I want to perform 
> are of the form,
>
>     foreach(x; myVeryLargeArray) {
>         assert(/* ... some condition about x */);
>     }
>
> ... and I'm concerned that with the foreach() loop in place, it 
> will slow down the code even if the assert() statements are 
> ignored at compile time.  So I'd like to be able to do 
> something instead like,
>
>     version(!release)
>     {
>         foreach(x; myVeryLargeArray) {
>             assert(/* ... some condition about x */);
>         }
>     }
>
> ... is this possible?

My suggestion is to use a pure helper predicate, possibly nothrow
too (a pure lambda too is OK):

bool isGood(MyType x) pure {
...
}

foreach(x; myVeryLargeArray) {
      assert(isGood(x));
}


The purity of the predicate is almost necessary, to be sure your
program behavior doesn't change between release and non-release
mode.

Bye,
bearophile