Easy overlay publishing

[roberth]

The goal here is to make a half-decent overlay easy to define, by overloading pkgs in perSystem.
Multiple kinds of overlays exist in flakes. This may not be the definitive way to define them, so it's not part of the core modules.

• documentation

Example:

# ...
{
      imports = [
        inputs.flake-parts.flakeModules.easyOverlay
      ];
      perSystem = { config, pkgs, final, ... }: {
        overlayAttrs = { inherit (config.packages) my-package; };
        # ...

[srid]

Tangential thought: could this sort of API be useful for haskell-flake in some way? cf. srid/haskell-flake#12

[roberth]

Tangential thought: could this sort of API be useful for haskell-flake in some way? cf. srid/haskell-flake#12

Responded there. I think a module would be easier to understand, and more capable.

In general I think we should avoid overlays where we can use modules instead. Combining the two concepts is tricky.

[shlevy]

This is really cool!