nixos-configs/packages/repl/default.nix

# modified from https://github.com/fufexan/dotfiles/blob/main/pkgs/repl/default.nix
{
  coreutils,
  gnused,
  ncurses,
  writeShellApplication,
  ...
}: let
  repl = ./repl.nix;
  example = command: desc: ''\n$(tput setaf 3) ${command}$(tput sgr0) - ${desc}'';
in
  writeShellApplication {
    name = "repl";

    runtimeInputs = [coreutils gnused ncurses];

    text = ''
      arg=''${1:-""}

      case "$arg" in
          "-h"|"--help"|"help")
              # shellcheck disable=SC2059
              printf "\n\e[4mUsage\e[0m: \
                  ${example "repl             " "Loads system flake present at $(tput setaf 4)\\$FLAKE$(tput sgr0)."} \
                  ${example "repl <flake path>" "Loads specified flake."}\n"
          ;;

          *)
              if [ -z "$arg" ]; then
                  nix repl \
                      --arg flakePath "$(realpath "$FLAKE")" \
                      --file ${repl}
              else
                  nix repl \
                      --arg flakePath "$(realpath "$arg" | sed 's|/flake.nix||')" \
                      --file ${repl}
              fi
          ;;
      esac
    '';
  }