Thoughts on versioning

[Andrei Alexandrescu]

On 10/26/21 9:36 PM, Adam D Ruppe wrote:
> On Wednesday, 27 October 2021 at 01:23:44 UTC, Basile B. wrote:
>> The A and W API are funadementally there because it's a C API.
> 
> That's irrelevant. They do actually overload it with macros.
> 
> The point is the old functions - the A ones - are kept around but simply 
> forward to the new functions - the W ones - after doing some 
> compatibility transformations.
> 
> That is a viable path for Phobos. The existing std.x functions can 
> forward to std.v2.x as appropriate.

It's interesting that both you and Sebastiaan mention an "inverted 
delta" of sorts whereby current std is redone to use std2.

The converse approach would be to do minimal changes on std and write 
the modified behavior in std2.

What are the comparative pros and cons of the two approaches?