{
  description = "Roc flake";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-21.11";
    rust-overlay.url = "github:oxalica/rust-overlay"; # rust from nixpkgs has some libc problems, this is patched in the rust-overlay
    zig.url = "github:roarkanize/zig-overlay"; # zig 8.1 is broken on nixpkgs for M1 macs
    flake-utils.url = "github:numtide/flake-utils"; # to easily make configs for all architectures
  };

  outputs = { self, nixpkgs, rust-overlay, zig, flake-utils }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        overlays = [ (import rust-overlay) ];
        pkgs = import nixpkgs { 
          inherit system overlays;
        };
        llvmPkgs = pkgs.llvmPackages_13;

        # get current working directory
        cwd = builtins.toString ./.;
        rust = pkgs.rust-bin.fromRustupToolchainFile "${cwd}/rust-toolchain.toml";

        linuxInputs = with pkgs; [
          valgrind # used in cli tests, see cli/tests/cli_run.rs
          vulkan-headers
          vulkan-loader
          vulkan-tools
          vulkan-validation-layers
          xorg.libX11
          xorg.libXcursor
          xorg.libXrandr
          xorg.libXi
          xorg.libxcb
          alsa-lib
        ];

        # zig 0.9.1 from pkgs is broken on aarch64-darwin, hence the workaround
        zig-toolchain = zig.packages.${system}."0.9.1";

        sharedInputs = (with pkgs; [
          # build libraries
          cmake
          git
          python3
          llvmPkgs.llvm.dev
          llvmPkgs.clang
          libxkbcommon
          pkg-config
          zig-toolchain # roc builtins are implemented in zig, see compiler/builtins/bitcode/

          # lib deps
          libffi
          libxml2
          ncurses
          zlib
          libiconv

          # faster builds - see https://github.com/rtfeldman/roc/blob/trunk/BUILDING_FROM_SOURCE.md#use-lld-for-the-linker
          llvmPkgs.lld
          # debugir

          rust
        ]);
      in {

        devShell = pkgs.mkShell {
          buildInputs = sharedInputs ++ linuxInputs;

          LLVM_SYS_130_PREFIX = "${llvmPkgs.llvm.dev}";
          NIX_GLIBC_PATH = if pkgs.stdenv.isLinux then "${pkgs.glibc_multi.out}/lib" else "";
          LD_LIBRARY_PATH = with pkgs;
            lib.makeLibraryPath
            ([ pkg-config stdenv.cc.cc.lib libffi ncurses zlib ] ++ linuxInputs);
          NIXPKGS_ALLOW_UNFREE = 1; # to run the editor with NVIDIA's closed source drivers
        };

    }
  );
}