default nix with src ./.

default.nix

@@ -0,0 +1,7 @@
+{ pkgs }:
+pkgs.rustPlatform.buildRustPackage rec {
+  pname = "mdbook-${version}";
+  version = "0.4.2";
+  src = ./.;
+  cargoSha256 = "0ch25ivww62j2kwsd20159hwjfyhfarwmqy9hqn1lv2vhfskry2b";
+}

shell.nix

@@ -1,9 +0,0 @@
-with import <nixpkgs> {};
-stdenv.mkDerivation {
-  name = "my-rust-env";
-  buildInputs = [
-    pkgs.cargo
-    pkgs.gcc
-    pkgs.rustup
-  ];
-}