Checking function parameters in Phobos

[Joseph Rushton Wakeling]

On 20/11/13 01:01, Andrei Alexandrescu wrote:
> There's been recent discussion herein about what parameter validation method
> would be best for Phobos to adhere to.
>
> Currently we are using a mix of approaches:
>
> 1. Some functions enforce()
>
> 2. Some functions just assert()
>
> 3. Some (fewer I think) functions assert(0)
>
> 4. Some functions don't do explicit checking, relying instead on lower-level
> enforcement such as null dereference and bounds checking to ensure safety.
>
> Each method has its place. The question is what guidelines we put forward for
> Phobos code to follow; we're a bit loose about that right now.

Regarding enforce() vs. assert(), a good rule that I remember having suggested 
to me was that enforce() should be used for actual runtime checking (e.g. 
checking that the input to a public API function has correct properties), 
assert() should be used to test logical failures (i.e. checking that cases which 
should never arise, really don't arise).

I've always followed that as a rule of thumb ever since.