Why An Overlay?

[AngleSideAngle]

Is there a design decision behind this project using an overlay to add ros packages to nixpkgs? From reading through the source code and examples, I couldn't find any indication that there's an advantage to distributing ros packages as an overlay, as opposed to having the package derivations in a separate flake from nixpkgs. Please let me know if I'm missing something...

Also, apologies if an issue wasn't the right way to ask this.

[lopsided98]

There's no fundamental difference between an overlay and a flake. You can use this repo as a flake, or as a traditional overlay. The only thing really missing from the flake is support for flattening the package namespace so you don't have to use legacyPackages, but that doesn't matter much in practice.

[lopsided98]

Flakes didn't exist when I started this project (or at least they weren't in common use), which explains why the flake support may seem a bit bolted on. I guess you could redesign it so that the packages were only available as flake outputs, but that would just limit possible use cases. I don't find flake package outputs particularly useful outside basic interactive usage. If I'm integrating a flake into a larger system I normally use the overlay output anyway.