does latest!-1 make sense?

[jdx]

I added the ability to subtract versions from aliases which is helpful to express things like "I want the latest 2 versions of nodejs", for example. Here is what it looks like currently:

# use lts version of nodejs
nodejs lts

# install 2 versions behind the latest lts
# (e.g.: 16 if lts is 18)
nodejs lts!-2

# install python-3.10 if the latest is 3.11
python latest!-0.1

What do people think? This is experimental so it can change. One thought I have is this isn't compatible with the other types of .tool-versions syntaxes like the following:

erlang  ref:master   # compile from vcs ref
golang  prefix:1.19  # uses the latest 1.19.x version—needed in case "1.19" is an exact match
shfmt   path:./shfmt # use a custom runtime

So maybe it would be better to do something like minus-major:lts or sub-1:lts? That might fit a bit better with existing alternatives.

[JoiHallecksM6]

The ability to subtract versions from aliases is a useful addition to the syntax and can make it easier for users to specify which versions they want to use. However, as you have noted, it may not be fully compatible with other syntaxes that are already in use.

Using "minus-major:lts" or "sub-1:lts" instead of "lts!-2" may indeed make the syntax more compatible with existing alternatives. It may also be helpful to consider adding documentation and examples for how to use this new syntax to avoid confusion for users who are not familiar with it.

Overall, it's great to see experimentation and innovation in syntax to make it more user-friendly and flexible. As long as the changes are well-documented and communicated clearly, they can provide significant benefits to users.

[jdx]

minus-major:ts doesn't work since you need to be able subtract 2 in the case of even/odd languages like nodejs. However sub-1:lts I think I like a lot more with the benefit of hindsight than the current syntax since it fits with the other types like path:, prefix:, and ref:. That would clean up the internal code a fair bit and also more consistent which would help people understand how to use this stuff.

Currently this is documented in the .tool-versions section, which made sense initially since that was the main place this was defined, however now with .rtx.toml it might be better if I called it out explicitly. The main reason I haven't done that is I just haven't figured out what to call these (as a collection) yet. "version types?" I feel that is too generic. In the code I call them "ToolVersionType".

[jdx]

started working on this: #556