d4: flake.nix and run.sh -> run-py.sh

2022/d4/.envrc

@@ -0,0 +1,4 @@
+if command -v nix-shell &> /dev/null
+    then
+    use flake
+fi

2022/d4/.gitignore

@@ -0,0 +1 @@
+.direnv

2022/d4/flake.nix

@@ -0,0 +1,41 @@
+{
+  description = "D4 AOC with Lua!";
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+  outputs = { nixpkgs, flake-utils, ... } @ inputs:
+    flake-utils.lib.eachSystem flake-utils.lib.defaultSystems (sys:
+      let
+        overlays = [ ];
+        pkgs = import nixpkgs { system = sys; overlays = overlays; };
+        shellHookAfter = ''
+          echo "The input files should be placed under ./data/{submission,example}.txt
+          echo "This problem only "
+        '';
+      in
+      rec {
+        devShell = devShell.lua;
+        devShell.lua = lib.mkShell {
+          nativeBuildInputs = [
+            pkgs.lua.withPackages
+            (luapkgs:
+              [ luapkgs.busted luapkgs.luafilesystem ]
+            )
+          ];
+          shellHook = ''
+            echo "> Lua runtime"
+            echo "Run ./run-lua.sh to see solution's output"
+          '' + shellHookAfter;
+        };
+        devShell.python = lib.mkShell {
+          nativeBuildInputs = [ pkgs.python3 ];
+          shellHook = ''
+            echo "> Python3 runtime"
+            echo "Run ./run-py.sh to see solution's output"
+          '' + shellHookAfter;
+
+        };
+      }
+    );
+}