Arbitrary Dart types (opaque)

Any Dart type can be passed to Rust. This is done by wrapping it with DartOpaque.

This library ensures that any Dart objects are always removed on the parent Dart thread.

Different from non-opaque types, opaque types are not copied/moved/reconstructed at all. For example, if you pass around a Dart object MyObject in arguments and return values, you will get the exact same object.

Example DartOpaque


pub fn get_dart_opaque(a: DartOpaque) { ... }
pub fn return_dart_opaque() -> DartOpaque { ... }

And use it in Dart:

var opaque = await api.getDartOpaque(() => '42');
Object answer_obj = await api.returnDartOpaque();
var fn = answer_obj as String Function();

Implementation details

As for how it is implemented as well as the design towards safety, please refer to this doc).