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6.4 Inbox

The (goblins actor-lib inbox) module provides an inbox actor that serves as a message queue. Messages can be written to and read from the inbox. The inbox can be also be closed to prevent further messages from accumulating.

When a message is read from the inbox it will return the next message if available. If no message is available it will return a promise. If the inbox is stopped it’ll break all pending unfulfilled promises.

Procedure: spawn-inbox ¶

Spawns a new inbox, returning three actors: read, write, and stop actor.

(use-modules (goblins)
             (goblins actor-lib inbox))

(define-values (inbox outbox stop)
  (spawn-inbox))

(define vow-to-first
  ($ inbox))

($ outbox 'first)
($ outbox 'second)

(on vow-to-first pk)
;;; (first)

(pk ($ inbox))
;;; (second)

(define vow-to-third (<- inbox))
($ stop)
(on vow-to-third #:catch (lambda (err) (pk 'err err)))
;;; (err inbox-closed)

Persistence Environment: inbox-env ¶