Add semver_lt/semver_gt/semver_eq/... functions

[t3hmrman]

Thanks for the awesome tool -- just has been a huge part of my daily workflow and I take it to "just" about every project I start now.

One thing I've often run into is the need to parse & check versions of dependencies cross-language/toolchain against each other, and checking/ensuring a certain version of semver often comes up.

For exact matches this is relatively simple, but it might be nice to do be able to do this a bit more semantically as a utility within just.

A somewhat contrived example of what I'd like to be able to do is:

dep := env_var_or_default("DEP", "dep")
dep_version := `dep --version` # let's pretend that this prints the semver version
dep_version_supported := if semver_gte(dep_version, "0.2.0") { "supported" } else { "not supported" }

check:
  echo "your dep version of dep ({{dep_version}}) is {{dep_version_supported}}"

Does this seem like something that makes sense as a part of just?

[casey]

This seems reasonable to me, although I'm definitely curious if other people would find this useful, since it seems a little niche to me.

We could get away with having a single function, semver_match. The semver spec can have an = in front of it, to assert that it's an exact match, e.g., semver_match(version, "=1.0.0"). I think this is supported by the semver rust library.

[casey]

And thank you for the kind words! I'm always super happy when people find just useful.

[t3hmrman]

This seems reasonable to me, although I'm definitely curious if other people would find this useful, since it seems a little niche to me.

Agreed -- I kind of squared this by thinking of it like a string manipulation problem? It's definitely unclear if it's something a ton of people want though...

We could get away with having a single function, semver_match. The semver spec can have an = in front of it, to assert that it's an exact match, e.g., semver_match(version, "=1.0.0"). I think this is supported by the semver rust library.

This would be much better, great idea -- I'll put up a PR with this setup.

And thank you for the kind words! I'm always super happy when people find just useful.

Absolutely no problem, useful is an understatement!