What is the externalSrc written in Simula.nix

[haruki7049]

In this repository, There is no externalSrc calling by any files, but /Simula.nix has externalSrc argument. What is the meaning of externalSrc originally?

[georgewsinger]

Used in https://github.com/SimulaVR/simula-nixos/blob/5e54aa5d76b71dbd13612ca9c453a84ed69e8221/simula.nix#L23

Discussed here: https://simulavr.com/blog/simula-on-nixos/

[haruki7049]

There is override function in all Derivation

https://ryantm.github.io/nixpkgs/using/overrides/

How about using override to set user's source, instead of externalSrc?

[haruki7049]

#225

This PR makes programs.simula.package shipped with .#nixosModules. Please check this PR, @georgewsinger.