add nix flake

Author: MESYETI

flake.nix

@@ -0,0 +1,50 @@
+{
+  description = "Callisto is a reverse polish notation programming language inspired by YSL-C3 and Forth";
+
+  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-24.05";
+
+  outputs = { nixpkgs, ... }:
+    let
+      supportedSystems = [ "x86_64-linux" "x86_64-darwin" "i686-linux" ];
+      forEachSupportedSystem = f: nixpkgs.lib.genAttrs supportedSystems (system: f {
+        pkgs = import nixpkgs { inherit system; };
+      });
+    in
+    {
+      packages =
+        forEachSupportedSystem
+          ({ pkgs }:
+            let
+              cac = pkgs.buildDubPackage rec {
+                pname = "cac";
+                name = pname;
+
+                src = ./.;
+                dubLock = ./dub-lock.json;
+
+                nativeBuildInputs = [ pkgs.makeWrapper ];
+
+                installPhase = ''
+                  runHook preInstall
+                  install -Dm755 cac -t $out/bin
+                  runHook postInstall
+                '';
+
+                postFixup = with pkgs; ''
+                  wrapProgram $out/bin/cac --prefix PATH : "${lib.makeBinPath [ nasm stdenv.cc uxn ]}"
+                '';
+              };
+            in
+            {
+              inherit cac;
+              default = cac;
+            });
+      devShells =
+        forEachSupportedSystem
+          ({ pkgs }: {
+            default = pkgs.mkShell {
+              packages = with pkgs; [ dmd dub nasm ];
+            };
+          });
+    };
+}