Delete native assets package

Author: simolus3

pubspec.yaml

@@ -6,5 +6,4 @@ environment:
 
 workspace:
   - sqlite3
-  - sqlite3_native_assets
-  - sqlite3/example/custom_extension_native_assets
+  - sqlite3/example/custom_extension

sqlite3/example/custom_extension/.gitignore

@@ -1,24 +1,37 @@
-# uuid.c example
+This shows how a custom SQLite extension can be linked with native assets.
 
-This example shows how to load SQLite extensions into Flutter apps using `sqlite3_flutter_libs`.
-As an example, it uses the [uuid.c](https://github.com/sqlite/sqlite/blob/master/ext/misc/uuid.c)
-extension, but other extensions can be adapted similarly.
+The extension (https://github.com/asg017/sqlite-vec) is built with a code asset that will download
+the extension as a prebuilt file from its GitHub releases.
 
-To build the extension:
+SQLite extensions are shared libraries that have a function called `sqlite3_$extensionName_init`.
+With the hook linking the extension, you can bind to that function with Dart:
 
-1. A `CMakeLists.txt` (in `src/`) is written for Android, Linux and Windows.
-2. On Android, the NDK is set up to point at the CMake builds in `android/build.gradle`.
-3. For macOS and iOS (which don't use CMake as a build tool), the `uuid.c` file is added
-   to `macos|ios/Classes` instead.
-4. Note that this example does not currently support WebAssembly. Loadable extensions don't
-   work on the web, but you can compile a custom `sqlite3.wasm` bundle with the desired extensions
-   included. The `../custom_wasm_build` example has an example for that setup.
+```dart
+@Native<Int Function(Pointer<Void>, Pointer<Void>, Pointer<Void>)>()
+external int sqlite3_vec_init(
+  Pointer<Void> db,
+  Pointer<Void> pzErrMsg,
+  Pointer<Void> pApi,
+);
+
+```
 
-This build setup includes a shared library with the extension in your app. To use it, load the
-`DynamicLibrary` and then load it into sqlite3 like this:
+This will then allow linking the extension:
 
 ```dart
-  sqlite3.ensureExtensionLoaded(
-    SqliteExtension.inLibrary(uuid.lib, 'sqlite3_uuid_init'),
-  );
+extension LoadVectorExtension on Sqlite3 {
+  void loadSqliteVectorExtension() {
+    ensureExtensionLoaded(
+      SqliteExtension(
+        Native.addressOf<
+          NativeFunction<
+            Int Function(Pointer<Void>, Pointer<Void>, Pointer<Void>)
+          >
+        >(sqlite3_vec_init).cast(),
+      ),
+    );
+  }
+}
 ```
+
+To try this example, run `dart run example/main.dart`.