Setup

Prerequisites

• Rust (stable)
• Flutter SDK
• flutter_rust_bridge_codegen CLI

Commands

# Dart / Flutter
flutter pub get                    # Install dependencies
flutter analyze                    # Static analysis
cd example && flutter run -d chrome  # Run example app

# Rust
cargo test --workspace             # Run all Rust tests
cargo check --workspace            # Check all crates compile

# FRB Codegen (from packages/modality/)
flutter_rust_bridge_codegen generate  # Regenerate Dart bindings

File Structure

• Directorycrates/

  • Directoryapi/ FRB API layer (rust_input entry)

    • …
  • Directorycore/ Core traits: Reducer, Component, Modality, Slot, Effects, StoreBackend

    • …
  • Directorysession/ Session, Doc, CompileCache, ReduceIntent, HasChildren

    • …
  • Directorysync/ Loro extensions, sync protocol

    • …
  • Directorydoc/ Documentation utilities

    • …
  • Directorymacros/ Derive macros (LoroMapWrite, etc.)

    • …
  • Directorymodality/

    • Directorywhiteboard/ Whiteboard modality

      • …
    • Directoryworksheet/ Worksheet modality

      • …
    • Directorylesson/ LessonPlan modality

      • …
    • Directoryassessment/ Assessment modality

      • …
  • Directoryplatform/

    • Directoryai/ AI bridge (chat context, tool dispatch)

      • …
    • Directoryexecutor/ Async executor

      • …
    • Directoryexport/ PDF export

      • …
    • Directoryremote/ ResourceClient (GraphQL), RemoteBackend

      • …
    • Directorystore/ LocalBackend (file-based persistence)

      • …
• Directorypackages/

  • Directorymodality/ Dart package with FRB bindings

    • Directorylib/src/rust/ Generated FRB output

      • …
    • flutter_rust_bridge.yaml
  • Directorymodality_editor/ Editor UI (property editors, canvas, chat)

    • …
• Directoryapps/

  • Directorystudio/ Studio app (main entry point)

    • …

Crate Roles

Crate	Role
modality_core	Pure traits + types. Zero platform deps.
modality_session	Session<M,I>, Doc<S>, CompileCache. Depends on core + doc.
modality_ai	AI bridge, chat context, tool dispatch. No Session knowledge.
modality_export	PDF export. No Session knowledge.
Modality crates	Implement Reducer + Component + Modality for each modality.
modality_rust / API	FRB entry point. Thin open/dispatch/close API.