add tilde/caret/wildcards support to nimble

[disruptek]

We are probably going to have to implement these in Nimble if we want them to be useful in public projects.

cc @genotrance

[genotrance]

Do you mean pathSubs?

[disruptek]

No, I mean the requires = statements in the .nimble. I modeled Nimph's off of those of Cargo. There are also some tests that might be helpful.

https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html

[disruptek]

You can now play with these using the roll command, if it helps.

I'm thinking that given the state of things in Nimbleland, it might be easiest to just patch Nimble to parse ~ and ^ as >=, since that's the only useful operator there anyway. I imagine that Nimble is parsing 3 as 3.*.*, as today we discovered that some packages exist with 1-dot (eg. 3.1) versions, and @Solitude managed to find one with 3-dots (eg. 1.2.3.4).

A better alternative might be to introduce another statement to the .nimble. I've long wanted a way to blacklist version ranges; see #82, so maybe we add a more advanced requires statement that can co-exist with a Nimble-friendly requires, but which carries additional syntax capabilities (caret/tilde/wildcard). While we're in there, we add deficiencies for #82 and then we've enhanced capabilities without breaking any existing packages or package managers. Nimble can upgrade to support caret/tilde/wildcard via requires (or the new statements) whenever it likes.

We would almost certainly have to implement #24 as well, of course.

Thoughts?