I'm building Caffeine, a compiler written in Gleam that compiles service expectations to reliability artifacts. This post documents how our new version manager works to aid in easier installation and maintenance of a local Caffeine installation.

Introducing Caffeine Version Manager (CVM)

Obligatory Preface

First things first, using cvm is not needed! It's totally reasonable to just use the caffeine_lang brew setup. It looks a bit like this:

Initial Install

brew tap brickell-research/caffeine

brew install caffeine_lang

And to check it worked:

➜ (rob)  caffeine -v
caffeine 4.6.2 (Brickell Research)

Updating

Normal brew update.

brew update

brew upgrade caffeine_lang

We have no plans to discontinue support for this. It will continue to be updated on every release as part of our unified release process.

Ok, so Why CVM?

Following my talk at Gleam Gathering, I wondered how well Caffeine would actually scale for larger source files. So, I worked with Claude and set up a performance test/benchmarking repo here.

It turns out there is a real scaling limit. Enter tail call optimization limitations in most JavaScript VM implementations... That's a post for another day. The important part here is I wanted to be able to test two different versions of Caffeine easily, side-by-side (in this case, one that was compiled with deno and one that was compiled with bun).

Thus, as a Rubyist, I thought "ah! We need our own rvm!"

CVM

So, we now have cvm repo here. Just like the normal language install, we automate GitHub releases on tag pushes and also push to our Homebrew tap. A typical cvm process looks like this.

Initial Install

Install.

brew tap brickell-research/caffeine

brew install cvm

Setup.

Add this to your path.

export PATH="$HOME/.cvm/current:$PATH"

Install latest.

cvm install latest

Ensure it worked.

➜ (rob)  caffeine -v
caffeine 4.6.2 (Brickell Research)

Update and Switch to a Different Version

First, see what is available.

cvm list-remote

Then install and use one of the options.

cvm install 4.5.1

cvm use 4.5.1

And finally, if you're lost or curious, see all the help options.

cvm help

That's it! Pretty similar to other programming language version manager tools.

Conclusion

So should I change my process to use cvm now? Maybe? Probably not though. The existing brew install process for the language proper works, has worked for a long time, and as I said, will continue to be a supported first class citizen. Furthermore, in writing this post, it became clear there are a lot more steps to using cvm... so at this time, we don't even plan to make this the well-documented recommended approach anyway. Just a fun one for anyone else who may find themselves using multiple versions of Caffeine locally!