Add nix flake dev environment

Author: outercloudstudio

.envrc

@@ -0,0 +1 @@
+use flake

flake.lock

@@ -0,0 +1,60 @@
+{
+  description = "A Nix-flake-based Scala development environment";
+
+  inputs.nixpkgs.url = "https://flakehub.com/f/NixOS/nixpkgs/0.1"; # unstable Nixpkgs
+
+  outputs =
+    { self, ... }@inputs:
+
+    let
+      javaVersion = 23; # Change this value to update the whole stack
+
+      supportedSystems = [
+        "x86_64-linux"
+        "aarch64-linux"
+        "x86_64-darwin"
+        "aarch64-darwin"
+      ];
+      forEachSupportedSystem =
+        f:
+        inputs.nixpkgs.lib.genAttrs supportedSystems (
+          system:
+          f {
+            pkgs = import inputs.nixpkgs {
+              inherit system;
+              overlays = [ inputs.self.overlays.default ];
+            };
+          }
+        );
+    in
+    {
+      overlays.default =
+        final: prev:
+        let
+          jdk = prev."jdk${toString javaVersion}";
+        in
+        {
+          sbt = prev.sbt.override { jre = jdk; };
+          scala = prev.scala_3.override { jre = jdk; };
+          mill = prev.mill.override { jre = jdk; };
+        };
+
+      devShells = forEachSupportedSystem (
+        { pkgs }:
+        {
+          default = pkgs.mkShellNoCC {
+            packages = with pkgs; [
+              scala
+              sbt
+              mill
+              coursier
+              verilator
+              gcc
+              gnumake
+              python3
+            ];
+          };
+        }
+      );
+    };
+}