r3-reactive-extensions

Name: r3-reactive-extensions
Author: Aaronontheweb

51installs98forks

How to install r3-reactive-extensions?

aaronontheweb/dotnet-skills/r3-reactive-extensions

$npx -y skills add Aaronontheweb/dotnet-skills --skill r3-reactive-extensions

Installs into the current project.

Summary

Build reactive/event-driven C# with R3 (Cysharp's modern reimplementation of Reactive Extensions). Covers the Observable<T>/Observer<T> model, the OnErrorResume error contract, async dispatch with AwaitOperation, Task/IAsyncEnumerable integration, TimeProvider/FrameProvider sched

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SKILL.md

1	# R3: Modern Reactive Extensions for .NET
2
3	R3 is [Cysharp's](https://github.com/Cysharp/R3) ground-up reimplementation of Reactive
4	Extensions — "the new future of dotnet/reactive and UniRx." It keeps the LINQ-over-events
5	programming model but rebuilds the core types, error contract, and scheduler to fix
6	long-standing problems in `System.Reactive` (Rx.NET). Use this skill when composing event
7	streams, UI input, timers, or push-based pipelines in C#.
8
9	Canonical sources (link to these from code and docs):
10	- Repository: https://github.com/Cysharp/R3
11	- README (full operator reference): https://github.com/Cysharp/R3/blob/main/README.md
12	- Author's design rationale: https://neuecc.medium.com/r3-a-new-modern-reimplementation-of-reactive-extensions-for-c-cf29abcc5826
13
14	## When to Use This Skill
15
16	Use this skill when:
17	- Composing events over time — UI input, sensor/feed updates, websocket messages, domain events
18	- You need operators like debounce, throttle, merge, combine-latest, distinct-until-changed
19	- Building MVVM state with `ReactiveProperty` / `BindableReactiveProperty`
20	- Bridging push-based streams with `Task` / `async` and `IAsyncEnumerable`
21	- Migrating from `System.Reactive`, UniRx, or `IObservable<T>` code
22	- You hit Rx pain points: subscriptions dying on exceptions, scheduler overhead, or leak hunting
23
24	Not the right tool for: request/response I/O (use `async/await`), bounded producer/consumer
25	with backpressure (use `System.Threading.Channels`), or server-side stream processing with
26	batching/backpressure (use Akka.NET Streams). R3, like all Rx, is **push-based with no
27	backpressure**. See the `csharp-concurrency-patterns` skill for choosing between these.
28
29	## Reference Files
30
31	- [rx-net-differences.md](rx-net-differences.md): Every meaningful difference vs System.Reactive (Rx.NET) — the new core types, the error model, operator renames, dropped APIs, the scheduler swap, and a migration checklist.
32	- [async-and-integration-patterns.md](async-and-integration-patterns.md): Common patterns — async dispatch with `AwaitOperation`, `Task` integration, `IAsyncEnumerable` round-tripping, `ReactiveProperty`/MVVM, subjects, and subscription lifecycle.
33	- [scheduling-and-concurrency.md](scheduling-and-concurrency.md): How R3 handles concurrent updates (the threading contract, `Synchronize`, `ObserveOn`), `TimeProvider` vs `FrameProvider`, when each is necessary, and deterministic testing with fake providers.
34
35	> Everything in this skill was validated empirically against R3 1.3.1. Captured output
36	> appears in the reference files as evidence.
37
38	---
39
40	## Why R3 Exists (the "why use it")
41
42	The author ([neuecc](https://neuecc.medium.com/r3-a-new-modern-reimplementation-of-reactive-extensions-for-c-cf29abcc5826))
43	built R3 to fix concrete defects in `System.Reactive`:
44
45	1. Exceptions silently kill subscriptions. In Rx, one exception in the pipeline calls
46	`OnError` and unsubscribes forever — "a billion-dollar mistake" for long-lived event
47	streams (a single bad UI event tears down the whole subscription). R3 routes errors to
48	`OnErrorResume` and keeps the subscription alive by default.
49	2. `IScheduler` is heavy and confusing. `ImmediateScheduler`/`Merge` were measured causing
50	real server memory/CPU bloat. R3 deletes `IScheduler` and uses .NET 8's `TimeProvider`
51	(wall-clock) plus a new `FrameProvider` (frame-clock).
52	3. Subscription leaks are hard to find. R3 makes every `Observable<T>` an abstract class so
53	all subscriptions funnel through one place, enabling `ObservableTracker` to list every live
54	subscription with stack traces.
55	4. Rx and async were awkwardly fused. R3 treats Rx as event-first and adds explicit
56	bridges (`AwaitOperation`, `FromAsync`, `ToAsyncEnumerable`) instead of pretending events
57	are pull-based sequences.
58	5. One library, every UI. A platform-neutral core plus thin provider packages for Unity,
59	Godot, WPF, WinForms, Avalonia, WinUI3, MAUI, Stride, MonoGame, and Blazor.
60
61	---
62
63	## Install
64
65	```bash
66	dotnet add package R3
67	# Platform glue (pick what applies): R3.WPF, R3.Avalonia, R3.WinForms, R3.Unity (UPM),
68	# R3.Godot, ObservableCollections.R3, etc. See the repo README for the full list.
69	```
70
71	```csharp
72	using R3;
73	```
74
75	---
76
77	## The Mental Model
78
79	R3 replaces Rx's interfaces with abstract classes, and replaces Rx's two-method error
80	contract with a single completion that carries a result.
81
82	```csharp
83	public abstract class Observable<T>
84	{
85	public IDisposable Subscribe(Observer<T> observer); // tracked centrally
86	p

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r3-reactive-extensions

51installs98forks

View on GitHub

How to install r3-reactive-extensions?

aaronontheweb/dotnet-skills/r3-reactive-extensions

$npx -y skills add Aaronontheweb/dotnet-skills --skill r3-reactive-extensions

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# R3: Modern Reactive Extensions for .NET
2
3	R3 is [Cysharp's](https://github.com/Cysharp/R3) ground-up reimplementation of Reactive
4	Extensions — "the new future of dotnet/reactive and UniRx." It keeps the LINQ-over-events
5	programming model but rebuilds the core types, error contract, and scheduler to fix
6	long-standing problems in `System.Reactive` (Rx.NET). Use this skill when composing event
7	streams, UI input, timers, or push-based pipelines in C#.
8
9	Canonical sources (link to these from code and docs):
10	- Repository: https://github.com/Cysharp/R3
11	- README (full operator reference): https://github.com/Cysharp/R3/blob/main/README.md
12	- Author's design rationale: https://neuecc.medium.com/r3-a-new-modern-reimplementation-of-reactive-extensions-for-c-cf29abcc5826
13
14	## When to Use This Skill
15
16	Use this skill when:
17	- Composing events over time — UI input, sensor/feed updates, websocket messages, domain events
18	- You need operators like debounce, throttle, merge, combine-latest, distinct-until-changed
19	- Building MVVM state with `ReactiveProperty` / `BindableReactiveProperty`
20	- Bridging push-based streams with `Task` / `async` and `IAsyncEnumerable`
21	- Migrating from `System.Reactive`, UniRx, or `IObservable<T>` code
22	- You hit Rx pain points: subscriptions dying on exceptions, scheduler overhead, or leak hunting
23
24	Not the right tool for: request/response I/O (use `async/await`), bounded producer/consumer
25	with backpressure (use `System.Threading.Channels`), or server-side stream processing with
26	batching/backpressure (use Akka.NET Streams). R3, like all Rx, is **push-based with no
27	backpressure**. See the `csharp-concurrency-patterns` skill for choosing between these.
28
29	## Reference Files
30
31	- [rx-net-differences.md](rx-net-differences.md): Every meaningful difference vs System.Reactive (Rx.NET) — the new core types, the error model, operator renames, dropped APIs, the scheduler swap, and a migration checklist.
32	- [async-and-integration-patterns.md](async-and-integration-patterns.md): Common patterns — async dispatch with `AwaitOperation`, `Task` integration, `IAsyncEnumerable` round-tripping, `ReactiveProperty`/MVVM, subjects, and subscription lifecycle.
33	- [scheduling-and-concurrency.md](scheduling-and-concurrency.md): How R3 handles concurrent updates (the threading contract, `Synchronize`, `ObserveOn`), `TimeProvider` vs `FrameProvider`, when each is necessary, and deterministic testing with fake providers.
34
35	> Everything in this skill was validated empirically against R3 1.3.1. Captured output
36	> appears in the reference files as evidence.
37
38	---
39
40	## Why R3 Exists (the "why use it")
41
42	The author ([neuecc](https://neuecc.medium.com/r3-a-new-modern-reimplementation-of-reactive-extensions-for-c-cf29abcc5826))
43	built R3 to fix concrete defects in `System.Reactive`:
44
45	1. Exceptions silently kill subscriptions. In Rx, one exception in the pipeline calls
46	`OnError` and unsubscribes forever — "a billion-dollar mistake" for long-lived event
47	streams (a single bad UI event tears down the whole subscription). R3 routes errors to
48	`OnErrorResume` and keeps the subscription alive by default.
49	2. `IScheduler` is heavy and confusing. `ImmediateScheduler`/`Merge` were measured causing
50	real server memory/CPU bloat. R3 deletes `IScheduler` and uses .NET 8's `TimeProvider`
51	(wall-clock) plus a new `FrameProvider` (frame-clock).
52	3. Subscription leaks are hard to find. R3 makes every `Observable<T>` an abstract class so
53	all subscriptions funnel through one place, enabling `ObservableTracker` to list every live
54	subscription with stack traces.
55	4. Rx and async were awkwardly fused. R3 treats Rx as event-first and adds explicit
56	bridges (`AwaitOperation`, `FromAsync`, `ToAsyncEnumerable`) instead of pretending events
57	are pull-based sequences.
58	5. One library, every UI. A platform-neutral core plus thin provider packages for Unity,
59	Godot, WPF, WinForms, Avalonia, WinUI3, MAUI, Stride, MonoGame, and Blazor.
60
61	---
62
63	## Install
64
65	```bash
66	dotnet add package R3
67	# Platform glue (pick what applies): R3.WPF, R3.Avalonia, R3.WinForms, R3.Unity (UPM),
68	# R3.Godot, ObservableCollections.R3, etc. See the repo README for the full list.
69	```
70
71	```csharp
72	using R3;
73	```
74
75	---
76
77	## The Mental Model
78
79	R3 replaces Rx's interfaces with abstract classes, and replaces Rx's two-method error
80	contract with a single completion that carries a result.
81
82	```csharp
83	public abstract class Observable<T>
84	{
85	public IDisposable Subscribe(Observer<T> observer); // tracked centrally
86	p

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