Motive behind !empty() with front() instead of Optional front()

[Andrei Alexandrescu]

On 3/24/21 3:23 PM, Per Nordlöw wrote:
> What's the motive behinds D's range design choice of needing
> 
>      if (!empty)
>      {
>          // use front or back
>      }
> 
> instead of having front returning an optional/maybe type with enforced 
> pattern matching?

Efficiency. It would be impossible to iterate an array as a range 
without copying each and every element thereof.

We investigated a few other possibilities, such as returning a pointer 
to the next element or null. But that has problems related to safety and 
escaping pointers.