no simplistic development example via shell.nix and direnv

[matu3ba]

Your examples assume that the user wants to build everything with flakes etc, but the user might also just want to reuse upstream as environment and use relative paths.

Reasoning:

• 1. found no simple way to reference via relative path other flakes etc on system.
• 2. shell.nix + direnv is the most simple way to get a reproducible dev setup
• 3. flakes and other methods copy things to global nix store and user might not want copies of files lying around

Paths:

~/dev/zdev/zig/
~/dev/zdev/zig-bootstrap/
~/dev/zdev/shell.nix
~/dev/zdev/.envrc
~/dev/zi/shell.nix
~/dev/zi/.envrc

~/dev/zdev/shell.nix

{ pkgs ? import (fetchTarball "https://github.com/NixOS/nixpkgs/archive/01441e14af5e29c9d27ace398e6dd0b293e25a54.tar.gz") {} }:
pkgs.stdenvNoCC.mkDerivation {
  name = "shell";
  nativeBuildInputs = with pkgs; [
      cmake
      gdb
      libxml2
      ninja
      python3
      qemu
      valgrind
      wasmtime
  ] ++ (with llvmPackages_16; [
    clang
    clang-unwrapped
    lld
    llvm
  ]);
}

~/dev/zi/shell.nix with shellHook example:

{ pkgs ? import (fetchTarball "https://github.com/NixOS/nixpkgs/archive/01441e14af5e29c9d27ace398e6dd0b293e25a54.tar.gz") {} }:
pkgs.stdenvNoCC.mkDerivation {
  name = "shell";
  nativeBuildInputs = with pkgs; [
      gdb
      qemu
      valgrind
      wasmtime
  ];
  PROJECT_ROOT = builtins.toString ./.;
  shellHook = ''
    PATH=$PATH:$PROJECT_ROOT/../zdev/zig/master/rel/bin/
  '';
}

[mimoo]

I think this guide was meant to be a "best practice to start a project with nix today", but things get more and more complicated/complex as you go through the guide