Architecture overview

Languages

简体中文

Repositories

Repository	Role
MvvmAIO.R3.SourceGenerators	Analyzers, tests, Nuke build
MvvmAIO.R3.SourceGenerators.Samples	WPF + Avalonia demos (separate clone)
R3.SourceGenerators.Docs (this site)	VitePress documentation

Solution layout

Primary solution: MvvmAIO.R3.SourceGenerators.slnx

Project / folder	Role
MvvmAIO.R3.SourceGenerators/MvvmAIO.R3.SourceGenerators/	Shared generator logic (.projitems; ObservableEvents/ + partial generators)
MvvmAIO.R3.SourceGenerators.Roslyn4031	Roslyn 4.3.1 analyzer build
MvvmAIO.R3.SourceGenerators.Roslyn4120	Roslyn 4.12 analyzer build
MvvmAIO.R3.SourceGenerators.Roslyn5000	Roslyn 5.0 analyzer build
MvvmAIO.R3.SourceGenerators.Package/	MvvmAIO.R3.SourceGenerators NuGet layout
MvvmAIO.R3.SourceGenerators.Tests/	Verify snapshots + test harness
build/	Nuke Ci, pack, publish

Generators

Generator	User API	Output
ObservableEventsGenerator	FromEvents, routed helpers	Internal event interfaces + sealed impls
R3CommandGenerator	[R3Command] on partial types	ReactiveCommand* properties

Observable events pipeline (summary)

1. Post-init (ObservableEventsGenerator.cs) — bootstrap for unresolved call sites (NullEvents).
2. Discovery (ObservableEventsGenerator.Discovery.cs) — collect invocation targets from user syntax.
3. Interface pipeline (InterfacePipeline → InterfaceEmission / GenericConstraints) — EventInterfaceDescriptor hierarchy → EventInterfaces.{kind}.g.cs + per-type *Impl files.
4. Attached routed (AttachedRouted) — Avalonia extensions returning Observable<T>.

Static ObservableEventsStatics generation is disabled. Contributor file layout: ObservableEventsGenerator.

R3Command pipeline (summary)

Post-init attribute registration, partial-type validation, signature matrix checks, optional CanExecute wiring.

Call-site driven generation

Code is emitted when your project calls an entry API (FromEvents(), FromRoutedEvents(), and so on) on a concrete type. The generator records those types and emits matching interfaces and sealed implementations on the next build.

Bootstrap and unresolved call sites

A small post-init layer provides fallback extensions (for example on object?) so incomplete solutions still compile. These stubs are hidden from typical IntelliSense in consuming assemblies; type-specific generated overloads win at real call sites. Types with no usable events may resolve to NullEvents until proper generation runs.

WPF vs Avalonia

Platform	Requirement
WPF routed events	<UseWPF>true</UseWPF> in the consumer project
Avalonia routed	RoutedEvent metadata on event symbols; parameterless overloads use default routes
Attached routed (Avalonia)	Separate FromAttachedRoutedEvent APIs — not the interface property model

Details: Observable events.

Generated file layout

See the Generated artifacts table on Observable events. Per-type files such as {Type}.FromEvents.g.cs sit beside shared EventInterfaces.*.g.cs bundles.

Not generated today

• Static observable helpers (OBS_* / ObservableEventsStatics) — disabled in current releases.
• Unsupported event delegates are skipped with R3SG2001 / R3SG2002 warnings.

Source map (contributors)

Area	Files
Observable events orchestration	ObservableEventsGenerator.cs (Initialize only)
Observable events (full map)	ObservableEventsGenerator — partials + ObservableEvents/*
Event syntax	ObservableEventsSyntaxFactory.cs
Bootstrap	GeneratorBootstrapSyntaxFactory.cs
Commands	R3CommandGenerator.cs, R3CommandSyntaxFactory.cs
Diagnostics	Diagnostics/DiagnosticDescriptors.cs

Canonical maintainer index: AGENTS.md in the generator repo.

See Roslyn targeting for analyzer selection.