diff --git a/flake.nix b/flake.nix
index 0655e39..0be246f 100644
--- a/flake.nix
+++ b/flake.nix
@@ -7,79 +7,6 @@
       overlays = [self.overlays.default];
     };
 
-    overlays.default = final: prev: {
-      racket-minimal = final.callPackage ./racket/minimal.nix {};
-      racket = final.callPackage ./racket/package.nix {};
-
-      racketPackages = final.lib.makeScope final.newScope (self: {
-        racketInstallHook = self.callPackage ./racket-install-hook.nix {};
-        buildRacketPackage = self.callPackage ./build-racket-package.nix {};
-
-        makeRacketEnv = self.callPackage ./make-racket-env.nix {};
-
-        testEnv = self.makeRacketEnv {
-          packages = [self.ansi-color self.curly-fn-lib];
-        };
-
-        ansi-color = self.callPackage (
-          {
-            lib,
-            buildRacketPackage,
-            fetchFromGitHub,
-          }: buildRacketPackage {
-            pname = "ansi-color";
-            version = "0.2";
-
-            src = final.fetchFromGitHub {
-              owner = "renatoathaydes";
-              repo = "ansi-color";
-              rev = "0.2";
-              hash = "sha256-7WDW+4R9K+XLb9nMNGQlU+zAi2Gq7cUqzO3csN+AJvI=";
-            };
-          }
-        ) {};
-
-        namespaced-transformer-lib = self.callPackage (
-          {
-            lib,
-            buildRacketPackage,
-            fetchFromGitHub,
-          }: buildRacketPackage {
-            pname = "namespaced-transformer-lib";
-            version = "none";
-
-            src = "${final.fetchFromGitHub {
-              owner = "lexi-lambda";
-              repo = "namespaced-transformer";
-              rev = "4cdc1bdae09a07b78f23665267f2c7df4be5a7f6";
-              hash = "sha256-vpDJ7qUNhKreig1LbU33d7TXXHkfd7gPxE1Fc5bvzFE=";
-            }}/namespaced-transformer-lib";
-          }
-        ) {};
-
-        curly-fn-lib = self.callPackage (
-          {
-            lib,
-            buildRacketPackage,
-            fetchFromGitHub,
-
-            namespaced-transformer-lib,
-          }: buildRacketPackage {
-            pname = "curly-fn-lib";
-            version = "none";
-
-            dependencies = [ namespaced-transformer-lib ];
-
-            src = "${final.fetchFromGitHub {
-              owner = "lexi-lambda";
-              repo = "racket-curly-fn";
-              rev = "d64cd71d5b386be85f5979edae6f6b6469a4df86";
-              hash = "sha256-ge7o/UAvUXA4DIl03UkqVnLHNaPGq4SqxWvpcKdXndI=";
-            }}/curly-fn-lib";
-          }
-        ) {};
-
-      });
-    };
+    overlays.default = import ./overlay.nix;
   };
 }
diff --git a/overlay.nix b/overlay.nix
new file mode 100644
index 0000000..0d9c077
--- /dev/null
+++ b/overlay.nix
@@ -0,0 +1,74 @@
+final: prev: {
+  racket-minimal = final.callPackage ./racket/minimal.nix {};
+  racket = final.callPackage ./racket/package.nix {};
+
+  racketPackages = final.lib.makeScope final.newScope (self: {
+    racketInstallHook = self.callPackage ./racket-install-hook.nix {};
+    buildRacketPackage = self.callPackage ./build-racket-package.nix {};
+
+    makeRacketEnv = self.callPackage ./make-racket-env.nix {};
+
+    testEnv = self.makeRacketEnv {
+      packages = [self.ansi-color self.curly-fn-lib];
+    };
+
+    ansi-color = self.callPackage (
+      {
+        lib,
+        buildRacketPackage,
+        fetchFromGitHub,
+      }: buildRacketPackage {
+        pname = "ansi-color";
+        version = "0.2";
+
+        src = final.fetchFromGitHub {
+          owner = "renatoathaydes";
+          repo = "ansi-color";
+          rev = "0.2";
+          hash = "sha256-7WDW+4R9K+XLb9nMNGQlU+zAi2Gq7cUqzO3csN+AJvI=";
+        };
+      }
+    ) {};
+
+    namespaced-transformer-lib = self.callPackage (
+      {
+        lib,
+        buildRacketPackage,
+        fetchFromGitHub,
+      }: buildRacketPackage {
+        pname = "namespaced-transformer-lib";
+        version = "none";
+
+        src = "${final.fetchFromGitHub {
+          owner = "lexi-lambda";
+          repo = "namespaced-transformer";
+          rev = "4cdc1bdae09a07b78f23665267f2c7df4be5a7f6";
+          hash = "sha256-vpDJ7qUNhKreig1LbU33d7TXXHkfd7gPxE1Fc5bvzFE=";
+        }}/namespaced-transformer-lib";
+      }
+    ) {};
+
+    curly-fn-lib = self.callPackage (
+      {
+        lib,
+        buildRacketPackage,
+        fetchFromGitHub,
+
+        namespaced-transformer-lib,
+      }: buildRacketPackage {
+        pname = "curly-fn-lib";
+        version = "none";
+
+        dependencies = [ namespaced-transformer-lib ];
+
+        src = "${final.fetchFromGitHub {
+          owner = "lexi-lambda";
+          repo = "racket-curly-fn";
+          rev = "d64cd71d5b386be85f5979edae6f6b6469a4df86";
+          hash = "sha256-ge7o/UAvUXA4DIl03UkqVnLHNaPGq4SqxWvpcKdXndI=";
+        }}/curly-fn-lib";
+      }
+    ) {};
+
+  });
+}