nix support for racket

implements nix helpers for building racket packages and environments

this is a complete new implementation of this functionality. i did not use racket2nix because racket2nix is messy and hasn't been updated for a while. this is a significantly simpler implementation owning to better use of stdenv utilities and racket features

how to use

make nix packages for racket packages

pkgs.racketPackages.callPackage (
  {
    lib,
    buildRacketPackage,
    fetchFromGitHub,
  }: buildRacketPackage {
    pname = "ansi-color";
    version = "0.2";

    src = final.fetchFromGitHub {
      owner = "renatoathaydes";
      repo = "ansi-color";
      rev = "0.2";
      hash = "sha256-7WDW+4R9K+XLb9nMNGQlU+zAi2Gq7cUqzO3csN+AJvI=";
    };
  }
) {}

automatic conversion from pkgs.racket-lang.org

racket2nix.rkt implements fetching catalog information for a package, converting the info to a nix expression, building the expression, and then refining the final expression with the source hash (TOFU), and other metadata from info.rkt

racket racket2nix.nix <pkgs> ...

this will create new files in racket-catalog which will then become available via eg nix build .#racketPackages.mypackage

build a racket environment

unfortunately, due to racket limitations, nix-shell/nix develop will not work at all for racket packages that are created using this nix code. instead, similar to python.buildEnv / python.withPackages, you can create a racket environment with a given set of packages in it. this functions somewhat like a python "virtualenv" for racket. it is implemented by creating a "tethered installation" -- see https://docs.racket-lang.org/raco/tethered-install.html.

with pkgs.racketPackages; makeRacketEnv {
  packages = [
    ansi-color
  ];
};

the resulting environment will have a bin/racket executable which has the declared packages available

future work

• add native library support to racket2nix
• allow using either racket or racket-minimal as a base (currently only racket non-minimal is supported)
• instead of having 2 separate packages, rework racket to be a layered installation on top of racket-minimal, reducing duplication. this is similar to how guix does it
• split outputs into bin/lib/doc/man etc