PuduLangMediator.Message

type: module path: "@root/src/PuduLangMediator/Message.pudu" fidelity: Active grammar: "[[grammar/pudu]]" depth_score: 0.6 depth_status: MEDIUM tags: [module, backbone] aliases: [PuduLangMediator.Message]

Purpose

What every kind of message shares: its Info (name, shape, tags), the Envelope a sender that names no types sends, and the Answer it gets back.

Interface

Signatures

export type Shape = Query | Command | Event | Sequence

export type Info = { name: Str, shape: Shape, tags: Array[Str] }

export type Envelope = { info: Info, packed: Erasure.Packed, summary: Str }

export type Fault = NoRoute(Str) | WrongKind(Str)

export type Delivery = Delivered(Erasure.Packed) | Undelivered(Fault) | Unheard

export type Answer = { info: Info, delivery: Delivery, failed: Bool, summary: Str }

export fn hasTag(info: &Info, tag: Str) -> Bool

export fn shapeName(shape: &Shape) -> Str

export fn failureOf[E](fault: &Fault) -> Messaging.Failure[E]

export fn answered[T, E](info: &Info, outcomes: &Erasure.Slot[Messaging.Outcome[T, E]], outcome: Messaging.Outcome[T, E]) -> Answer

export fn undelivered(info: &Info, fault: Fault) -> Answer

export fn unheard(info: &Info) -> Answer

export fn read[T, E](outcomes: &Erasure.Slot[Messaging.Outcome[T, E]], answer: &Answer) -> Option[Messaging.Outcome[T, E]]

export fn sealed[M](info: &Info, messages: &Erasure.Slot[M], message: M) -> Envelope

Linkage

• Requires: [[src/PuduLangMediator]], [[src/PuduLangMediator/Utils/Erasure]].
• Consumed by: [[src/PuduLangMediator/Behaviors/Logging]], [[src/PuduLangMediator/Catalog]], [[src/PuduLangMediator/Compose]], [[src/PuduLangMediator/Mediator]], [[src/PuduLangMediator/Notification]], [[src/PuduLangMediator/Open]], [[src/PuduLangMediator/Publisher]], [[src/PuduLangMediator/Request]], [[src/PuduLangMediator/Sender]], [[src/PuduLangMediator/Stream]].

Algorithm

1. sealed packs a message through its kind's message slot and keeps its show as the summary.
2. answered packs an outcome through its kind's outcome slot and records whether it failed and how it reads.
3. read unpacks an answer's outcome; an undelivered answer reads as Unhandled or Mismatched for any type; an unheard one reads as nothing here and as success through its notification kind.

Negative Logic (Prohibited Paths)

• An answer never reads back through another kind's slot.

Edge Cases

• A notification envelope whose kind has no handler is Unheard: not failed, summarized Ok(()).

Depth

DEPTH 0.6 (MEDIUM). Tested by the suite mirroring this module under test/.

Grill Log

• Q: Why separate Unheard from Undelivered? A: Publishing to nobody succeeds, sending to nobody fails; one variant could not answer both truthfully. _Rejected:_ treating an unheard publication as unhandled (a quiet event would look like an error).

Referenced by

[[domain/Erasure]] · [[src/PuduLangMediator]] · [[src/PuduLangMediator/Behaviors/Logging]] · [[src/PuduLangMediator/Catalog]] · [[src/PuduLangMediator/Compose]] · [[src/PuduLangMediator/Mediator]] · [[src/PuduLangMediator/Notification]] · [[src/PuduLangMediator/Open]] · [[src/PuduLangMediator/Publisher]] · [[src/PuduLangMediator/Request]] · [[src/PuduLangMediator/Sender]] · [[src/PuduLangMediator/Stream]] · [[src/PuduLangMediator/Utils/Erasure]] · [[src/PuduLangMediator/_MOC]]