merge codegen into main crate

codegen.nix

@@ -0,0 +1,23 @@
+{
+  stdenv,
+  rustPlatform,
+  lib,
+}: let
+  inherit (lib.sources) sourceByRegex;
+  src = sourceByRegex ./. ["Cargo.*" "(src|benches|tests|test_data)(/.*)?"];
+in
+  rustPlatform.buildRustPackage {
+    pname = "demostf-parser-codegen";
+    version = "0.1.0";
+
+    src = lib.traceVal src;
+
+    buildType = "debug";
+    buildFeatures = ["codegen"];
+
+    doCheck = false;
+
+    cargoLock = {
+      lockFile = ./Cargo.lock;
+    };
+  }