PuduLangLog.Sinks.Observable

type: module path: "@root/src/PuduLangLog/Sinks/Observable.pudu" fidelity: Active grammar: "[[grammar/pudu]]" depth_score: 0.4 depth_status: MEDIUM tags: [module, sink] aliases: [PuduLangLog.Sinks.Observable]

Purpose

Hands every event to subscribed observers, for in-process consumers such as live views and tests.

Interface

Signatures

export type Observer = { next: fn(&Log.Event) -> (), completed: fn() -> () }

export type Subscription = { id: Int }

export type Observable = { observers: Sync.Cell[Array[(Int, Observer)]], issued: Sync.Counter, ended: Sync.Cell[Bool], lock: Sync.Mutex }

export fn create() -> Observable

export fn observer(next: fn(&Log.Event) -> ()) -> Observer

export fn subscribe(subject: &Observable, watcher: Observer) -> Subscription

export fn unsubscribe(subject: &Observable, subscription: Subscription) -> ()

export fn count(subject: &Observable) -> Int

export fn sink(subject: &Observable) -> Sink.Sink

Linkage

• Requires: [[src/PuduLangLog]], [[src/PuduLangLog/Sink]], Std.Sync.
• Consumed by: package users.

Algorithm

1. Subscriptions are numbered; unsubscribing removes that observer only.
2. Events reach observers in subscription order.
3. Closing the sink ends the stream: each observer's completed runs once and the observers are removed.

Negative Logic (Prohibited Paths)

• An observer subscribing after the end is told at once and never receives events.

Edge Cases

• Unsubscribing twice does nothing.

Depth

DEPTH 0.4 (MEDIUM). Tested by test/PuduLangLog/Sinks/ObservableTest.

Grill Log

• Q: Why completed on close? A: A consumer waiting for more events needs to know none will come. _Rejected:_ closing silently.

Referenced by

[[CHANGELOG]] · [[seams/Sink]] · [[src/PuduLangLog/_MOC]] · [[subsystems/Sinks]]