Versioning Haskell: Semver <> PVP

semver-pvp.md

I personally prefer Semver. I think it's reasonable, simple, and makes sense. But as a good Haskell citizen, I'd like to be PVP-compliant as well. Here is a bit of a graphic showing how the two systems are almost the same:

PVP:            A . B     . C     . ...
Semver:             Major . Minor . Patch
                    ^       ^       ^
                    |       |       |
                    |       |       ` increment for other changes
                    |       |
                    |       ` increment on non-breaking change
                    |
                    ` increment on breaking change

Basically, PVP's A is useless from a compatibility standpoint. It's just a bystander in the "increment A.B for breaking changes" rule. So I just set it to 0 and never change it. The remaining 3 components then follow Semver.

So for any of my packages, you can interpret versions as: 0.Major.Minor.Patch

Regardless of how I'm bringing a SemVer perspective, or being PVP compliant, the version is the version: whatever string comes after version: in my package.yaml. Intention or perspective doesn't matter once it's been set for the package.

Well, we cannot write arbitrary version numbers after version: in package.yaml. Stack fails to build if I write 1.0.0-alpha.1 in my package.yaml.

That's why I have to include how to deal with this limitation in my process :-/