Reactive Wasm Web-Components with Embedded Swift

Based on Elementary.

Check out the "Swiftle" demo app: https://sliemeobn.github.io/elementary-dom/

Highly experimental, do not use.

Developed with a recent snapshot of swift. No WASM/WASI SDK required when built for Embedded (see Examples)

Things to figure out

• identity system and list-diffing
• lifecycle events and proper "unmounting" (currently node are just "dropped")
• @State system
• typed event handlers
• @Environment system
• dependencies on versioned packages (ie: build without unsafe flags)
• fix DOM not child-diffing to preserve animations/node (the current solution based on replaceChildren will not work it seems)
• "model-bindings" for inputs (ie: bind a @Binding to a textbox, or bind a @Binding on a check box)
• maybe conditionally support @Observable for non-embedded builds?
• transitions and animations (CSS-based)
• figure out why @Environment with optional ReactiveObject does not build in embedded
• proper unit testing (once APIs firms up a bit more)
• preference system (ie: bubbling up values)
• embedded-friendly Browser APIs (Storage, History, maybe in swiftwasm package with new JavaScriptKit macros)
• think about how to deal with the lack of Codable in embedded (wait for new serialization macros)
• make printing work without WASI (maybe pipe putchar through to javascript?)
• isolation and @MainActor stuff for reusable types (server-side-rendering and client apps)
• decide whether the current idea of Views flattening themselves into renderalbe types is even necessary, or if views should just "apply" themselves into the reconciler - might be a bit messier, but maybe faster and more flexible

Embedded Swift for WASM waitlist

• simple build with SwiftPM (wasm-ld)
• _Concurrency module (Task)
• Synchronization (Mutex)
• Codable (we probably need another way to JSON-ify things)

License and Derived Code

This package is generally licensed as Apache 2.

The Rectivity module is inspired by the Swift stdlib's Observation framework, and code in ReactivityMacros is directly derived from it (source). Find a copy of the Swift.org open source project license here.

This project includes binaries from the wasi-libc project, which is licensed under the Apache License 2.0 with LLVM Exceptions.