Thoughts on versioning

[Andrei Alexandrescu]

On 10/26/21 10:08 PM, zjh wrote:
> On Wednesday, 27 October 2021 at 01:58:07 UTC, zjh wrote:
>> On Wednesday, 27 October 2021 at 01:17:54 UTC, zjh wrote:
> 
> while the old `std`, you only need to add `using std = std2021;`, Then 
> change it to our forwarding code(compile time forwarding).
> Through compile time forwarding, the user's code speed should not change.
> 

We tried a number of approaches along these lines, we couldn't make 
anything work. My learning bit has been that you must modify code to 
make it versionable.