version(number) is completely useless

[Walter Bright]

On 7/19/2022 6:34 PM, Steven Schveighoffer wrote:
> The thing I miss the most for versions is a `version1 or version2` mechanism. I 
> doubt we will ever convince Walter this is a good idea.

I know what will happen if that is allowed, and it is not pretty.

The idea is to encourage people to work at teasing out just what should be a 
version and what shouldn't be, not have arithmetic decide what it is.

This can be faked with `static if` and some enums. Long ago, some users decided 
that druntime would be better served using `static if` arithmetic on enums 
instead of versions. Of course, what quickly emerged was the usual C snarl, and 
nobody knew what code was being compiled (it was made even worse by mutual 
dependencies). The problem was dropped in my lap, because nobody could figure it 
out. I didn't even try to figure it out, I figured out what the versions should 
be and removed all that `static if` nonsense.

If version arithmetic was added, it is guaranteed to produce a coding horror. 
But by then it will be too late to change our minds, and you and I will be stuck 
in hell.

At least using `static if` on enums as versioning I have managed to discourage, 
like using operator overloading for I/O. It's also why enums cannot be set on 
the command line :-)


> But in any case, we have the numeric versions, which are 100% useless (because, 
> as you say, they are not scoped to any dependencies), it would make sense to at 
> least make that feature useful.

Yes, the numbers are a failed idea of mine. I'd endorse deprecating them.