feat: add nix setup for marzipan

marzipan/nix/system.nix

@@ -0,0 +1,47 @@
+ctx: ctx.scoped rec {
+  inherit (ctx.system) pkgs;
+  inherit (ctx.flake.inputs) poetry2nix flake-utils;
+  inherit (pkgs) mkShellNoCC writeShellApplication;
+  inherit (flake-utils.lib) mkApp;
+
+  poetryCtx = poetry2nix.lib.mkPoetry2Nix { inherit pkgs; };
+  inherit (poetryCtx) mkPoetryEnv mkPoetryApplication;
+
+  deps = [poetryEnv];
+  dev-deps = [] 
+    ++ deps
+    ++ [poetryHyugaEnv]
+    ++ (with pkgs; [poetry]);
+
+  poetryCfg = ctx.config.poetry // { overrides = poetryOverrides; };
+  poetryEnv = mkPoetryEnv poetryCfg;
+
+  poetryHyugaCfg = poetryCfg // { projectDir = ./hyuga; };
+  poetryHyugaEnv = mkPoetryEnv poetryHyugaCfg;
+
+  poetryOverrides = poetryCtx.defaultPoetryOverrides.extend (final: prev: {
+    hyuga = prev.hyuga.overridePythonAttrs (old: {
+        buildInputs = []
+          ++ (old.buildInputs or [ ])
+          ++ [ final.poetry-core ];
+        preferWheel = true;
+      }
+    );
+  });
+
+  result.packages.default = mkPoetryApplication poetryCfg;
+  result.devShells.default = mkShellNoCC {
+    packages = dev-deps;
+  };
+
+  result.apps.replPython = mkShellApp "python-repl" ''python'';
+  result.apps.replHy = mkShellApp "hy-repl" ''hy'';
+
+  mkShellApp = (name: script: mkApp {
+    drv = writeShellApplication {
+      inherit name;
+      text = script;
+      runtimeInputs = dev-deps;
+    };
+  });
+}