Add initial snowfall-lib and treefmt setup

flake.nix

@@ -0,0 +1,70 @@
+{
+  description = "A simple base flake to be used as a starting point to avoid setting up everything for every flake";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.05";
+    snowfall-lib = {
+      url = "github:snowfallorg/lib";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    treefmt-nix = {
+      url = "github:numtide/treefmt-nix";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+      };
+    };
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      snowfall-lib,
+      treefmt-nix,
+    }:
+    let
+      forEachSystem = systems: map: nixpkgs.lib.genAttrs systems map;
+    in
+    {
+      lib.mkFlake =
+        options@{
+          systems ? [
+            "x86_64-linux"
+            "aarch64-linux"
+            "aarch64-darwin"
+          ],
+          devShellPackages ? (pkgs: [ ]),
+          treeFmtFile ? ./treefmt.nix,
+          ...
+        }:
+        let
+          snowfallOptions = builtins.removeAttrs options [
+            "systems"
+            "devShellPackages"
+            "treeFmtFile"
+          ];
+        in
+        (
+          snowfall-lib.lib.mkFlake snowfallOptions
+          // (forEachSystem systems (
+            system:
+            let
+              pkgs = import nixpkgs { inherit system; };
+              treeFmtEval = treefmt-nix.lib.evalModule pkgs treeFmtFile;
+            in
+            {
+              formatter = treeFmtEval.config.build.wrapper;
+              checks = {
+                fmt = treeFmtEval.config.build.check self;
+              };
+              devShells.default = pkgs.mkShell {
+                packages = [
+                  pkgs.nixfmt-rfc-style
+                  pkgs.nixd
+                ] ++ (devShellPackages pkgs);
+              };
+            }
+          ))
+        );
+    };
+}