1 ;;; 8sync --- Asynchronous programming for Guile
2 ;;; Copyright (C) 2016 Christopher Allan Webber <cwebber@dustycloud.org>
4 ;;; This file is part of 8sync.
6 ;;; 8sync is free software: you can redistribute it and/or modify it
7 ;;; under the terms of the GNU Lesser General Public License as
8 ;;; published by the Free Software Foundation, either version 3 of the
9 ;;; License, or (at your option) any later version.
11 ;;; 8sync is distributed in the hope that it will be useful,
12 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
13 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 ;;; GNU Lesser General Public License for more details.
16 ;;; You should have received a copy of the GNU Lesser General Public
17 ;;; License along with 8sync. If not, see <http://www.gnu.org/licenses/>.
19 (define-module (8sync actors)
20 #:use-module (oop goops)
21 #:use-module (srfi srfi-9)
22 #:use-module (srfi srfi-9 gnu)
23 #:use-module (ice-9 control)
24 #:use-module (ice-9 format)
25 #:use-module (ice-9 match)
26 #:use-module (ice-9 pretty-print)
27 #:use-module (8sync agenda)
28 #:export (;; utilities... ought to go in their own module
30 big-random-number-string
31 simple-message-id-generator
39 ;;; Commenting out the <address> type for now;
40 ;;; it may be back when we have better serializers
43 address-actor-id address-hive-id
58 ;; There are more methods for the hive, but there's
59 ;; no reason for the outside world to look at them maybe?
61 hive-create-actor hive-create-actor*
63 create-actor create-actor*
68 message-to message-action message-from
69 message-id message-body message-in-reply-to
74 <- <-* <-wait <-wait* <-reply <-reply* <-reply-wait <-reply-wait*
76 call-with-message msg-receive msg-val
81 serialize-message write-message
82 serialize-message-pretty pprint-message
83 read-message read-message-from-string))
87 (make-parameter (random-state-from-platform)))
89 ;; Same size as a uuid4 I think...
90 (define random-number-size (expt 2 128))
92 (define (big-random-number)
93 (random random-number-size (%random-state)))
95 ;; Would be great to get this base64 encoded instead.
96 (define (big-random-number-string)
97 ;; @@: This is slow. Using format here is wasteful.
98 (format #f "~x" (big-random-number)))
100 ;; @@: This is slow. A mere ~275k / second on my (old) machine.
101 ;; The main cost seems to be in number->string.
102 (define (simple-message-id-generator)
103 ;; Prepending this cookie makes message ids unique per hive
104 (let ((prefix (format #f "~x:" (big-random-number)))
107 (set! counter (1+ counter))
108 (string-append prefix (number->string counter)))))
116 ;; @@: We may want to add a deferred-reply to the below, similar to
117 ;; what we had in XUDD, for actors which do their own response
118 ;; queueing.... ie, that might receive messages but need to shelve
119 ;; them to be acted upon after something else is taken care of.
121 (define-record-type <message>
122 (make-message-intern id to from action
123 body in-reply-to wants-reply
126 (id message-id) ; id of this message
127 (to message-to) ; actor id this is going to
128 (from message-from) ; actor id of sender
129 (action message-action) ; action (a symbol) to be handled
130 (body message-body) ; argument list "body" of message
131 (in-reply-to message-in-reply-to) ; message id this is in reply to, if any
132 (wants-reply message-wants-reply) ; whether caller is waiting for reply
133 (replied message-replied ; was this message replied to?
134 set-message-replied!))
137 (define* (make-message id to from action body
138 #:key in-reply-to wants-reply
140 (make-message-intern id to from action body
141 in-reply-to wants-reply replied))
143 (define (message-auto-reply? message)
144 (eq? (message-action message) '*auto-reply*))
146 (define (message-needs-reply? message)
147 "See if this message needs a reply still"
148 (and (message-wants-reply message)
149 (not (message-replied message))))
152 (define (kwarg-list-to-alist args)
153 (let loop ((remaining args)
156 (((? keyword? key) val rest ...)
158 (cons (cons (keyword->symbol key) val)
161 (_ (throw 'invalid-kwarg-list
162 "Invalid keyword argument list"
166 ;;; See: https://web.archive.org/web/20081223021934/http://mumble.net/~jar/articles/oo-moon-weinreb.html
167 ;;; (also worth seeing: http://mumble.net/~jar/articles/oo.html )
169 ;; This is the internal, generalized message sending method.
170 ;; Users shouldn't use it! Use the <-foo forms instead.
172 ;; @@: Could we get rid of some of the conditional checks through
175 (define-inlinable (send-message send-options from-actor to-id action
176 replying-to-message wants-reply?
178 (if replying-to-message
179 (set-message-replied! replying-to-message #t))
180 (let* ((hive (actor-hive from-actor))
182 (make-message (hive-gen-message-id hive) to-id
183 (actor-id from-actor) action
185 #:wants-reply wants-reply?
187 (if replying-to-message
188 (message-id replying-to-message)
191 (abort-to-prompt (hive-prompt (actor-hive from-actor))
192 from-actor new-message send-options)
193 ;; @@: It might be that eventually we pass in send-options
194 ;; here too. Since <-wait and <-reply-wait are the only ones
195 ;; that use it yet, for now it kind of just makes things
197 (8sync (hive-process-message hive new-message)))))
199 (define (<- to-id action . message-body-args)
200 "Send a message from an actor to another actor"
201 (send-message '() (%current-actor) to-id action
202 #f #f message-body-args))
204 (define (<-* send-options to-id action . message-body-args)
205 "Like <-*, but allows extra parameters via send-options"
206 (define* (really-send #:key (actor (%current-actor))
208 (send-message send-options actor to-id action
209 #f #f message-body-args))
210 (apply really-send send-options))
212 (define (<-wait to-id action . message-body-args)
213 "Send a message from an actor to another, but wait until we get a response"
214 (wait-maybe-handle-errors
215 (send-message '() (%current-actor) to-id action
216 #f #t message-body-args)))
218 (define (<-wait* send-options to-id action . message-body-args)
219 "Like <-wait, but allows extra parameters, for example whether to
221 (define* (really-send #:key (actor (%current-actor))
223 (apply wait-maybe-handle-errors
224 (send-message send-options actor to-id action
225 #f #t message-body-args)
227 (apply really-send send-options))
229 ;; TODO: Intelligently ~propagate(ish) errors on -wait functions.
230 ;; We might have `send-message-wait-brazen' to allow callers to
231 ;; not have an exception thrown and instead just have a message with
232 ;; the appropriate '*error* message returned.
234 (define (<-reply original-message . message-body-args)
236 (send-message '() (%current-actor) (message-from original-message) '*reply*
237 original-message #f message-body-args))
239 (define (<-reply* send-options original-message . message-body-args)
240 "Like <-reply, but allows extra parameters via send-options"
241 (define* (really-send #:key (actor (%current-actor))
243 (send-message send-options actor
244 (message-from original-message) '*reply*
245 original-message #f message-body-args))
246 (apply really-send send-options))
248 (define (<-auto-reply actor original-message)
249 "Auto-reply to a message. Internal use only!"
250 (send-message '() actor (message-from original-message) '*auto-reply*
251 original-message #f '()))
253 (define (<-reply-wait original-message . message-body-args)
254 "Reply to a messsage, but wait until we get a response"
255 (wait-maybe-handle-errors
256 (send-message '() (%current-actor)
257 (message-from original-message) '*reply*
258 original-message #t message-body-args)))
260 (define (<-reply-wait* send-options original-message
262 "Like <-reply-wait, but allows extra parameters via send-options"
263 (define* (really-send #:key (actor (%current-actor))
265 (apply wait-maybe-handle-errors
266 (send-message send-options actor
267 (message-from original-message) '*reply*
268 original-message #t message-body-args)
270 (apply really-send send-options))
272 (define* (wait-maybe-handle-errors message
275 "Before returning a message to a waiting caller, see if we need to
276 raise an exception if an error."
277 (define action (message-action message))
278 (cond ((and (eq? action '*error*)
280 (throw 'hive-unresumable-coroutine
281 "Won't resume coroutine; got an *error* as a reply"
287 ;;; Main actor implementation
288 ;;; =========================
290 (define (actor-inheritable-message-handler actor message)
291 (define action (message-action message))
292 (define (find-message-handler return)
293 (for-each (lambda (this-class)
295 (or (and (class-slot-definition this-class 'actions)
296 (class-slot-ref this-class 'actions))
298 (for-each (match-lambda
299 ((action-name . method)
300 (when (eq? action-name action)
303 (class-precedence-list (class-of actor)))
304 (throw 'action-not-found
305 "No appropriate action handler found for actor"
310 (call/ec find-message-handler))
311 (apply method actor message (message-body message)))
313 (define-syntax-rule (build-actions (symbol method) ...)
314 "Construct an alist of (symbol . method), where the method is wrapped
315 with wrap-apply to facilitate live hacking and allow the method definition
316 to come after class definition."
319 (wrap-apply method)) ...))
321 (define-class <actor> ()
323 (id #:init-keyword #:id
325 ;; The hive we're connected to.
326 ;; We need this to be able to send messages.
327 (hive #:init-keyword #:hive
328 #:accessor actor-hive)
329 ;; How we receive and process new messages
330 (message-handler #:init-value actor-inheritable-message-handler
331 ;; @@: There's no reason not to use #:class instead of
332 ;; #:each-subclass anywhere in this file, except for
333 ;; Guile bug #25211 (#:class is broken in Guile 2.2)
334 #:allocation #:each-subclass
335 #:getter actor-message-handler)
337 ;; This is the default, "simple" way to inherit and process messages.
338 (actions #:init-value (build-actions
339 ;; Default cleanup method is to do nothing.
340 (*cleanup* (const #f)))
341 #:allocation #:each-subclass))
343 ;;; So these are the nicer representations of addresses.
344 ;;; However, they don't serialize so easily with scheme read/write, so we're
345 ;;; using the simpler cons cell version below for now.
347 ;; (define-record-type <address>
348 ;; (make-address actor-id hive-id) ; @@: Do we want the trailing -id?
350 ;; (actor-id address-actor-id)
351 ;; (hive-id address-hive-id))
353 ;; (set-record-type-printer!
355 ;; (lambda (record port)
356 ;; (format port "<address: ~s@~s>"
357 ;; (address-actor-id record) (address-hive-id record))))
360 (define (make-address actor-id hive-id)
361 (vector actor-id hive-id))
363 (define (address-actor-id address)
364 (vector-ref address 0))
366 (define (address-hive-id address)
367 (vector-ref address 1))
369 (define (address->string address)
370 (string-append (address-actor-id address) "@"
371 (address-hive-id address)))
373 (define-method (actor-id-actor (actor <actor>))
374 "Get the actor id component of the actor-id"
375 (address-actor-id (actor-id actor)))
377 (define-method (actor-id-hive (actor <actor>))
378 "Get the hive id component of the actor-id"
379 (address-hive-id (actor-id actor)))
381 (define-method (actor-id-string (actor <actor>))
382 "Render the full actor id as a human-readable string"
383 (address->string (actor-id actor)))
385 (define %current-actor
388 (define (actor-alive? actor)
389 (hive-resolve-local-actor (actor-hive actor) (actor-id actor)))
396 (define-syntax-rule (define-simple-actor class action ...)
397 (define-class class (<actor>)
398 (actions #:init-value (build-actions action ...)
399 #:allocation #:each-subclass)))
404 ;;; Every actor has a hive. The hive is a kind of "meta-actor"
405 ;;; which routes all the rest of the actors in a system.
407 (define-generic hive-handle-failed-forward)
409 (define-class <hive> (<actor>)
410 (actor-registry #:init-thunk make-hash-table
411 #:getter hive-actor-registry)
412 (msg-id-generator #:init-thunk simple-message-id-generator
413 #:getter hive-msg-id-generator)
414 ;; Ambassadors are used (or will be) for inter-hive communication.
415 ;; These are special actors that know how to route messages to other hives.
416 (ambassadors #:init-thunk make-weak-key-hash-table
417 #:getter hive-ambassadors)
418 ;; Waiting coroutines
419 ;; This is a map from cons cell of message-id
420 ;; to a cons cell of (actor-id . coroutine)
421 ;; @@: Should we have a <waiting-coroutine> record type?
422 ;; @@: Should there be any way to clear out "old" coroutines?
423 (waiting-coroutines #:init-thunk make-hash-table
424 #:getter hive-waiting-coroutines)
426 ;; When actors send messages to each other they abort to this prompt
427 ;; to send the message, then carry on their way
428 (prompt #:init-thunk make-prompt-tag
429 #:getter hive-prompt)
430 (actions #:allocation #:each-subclass
433 ;; This is in the case of an ambassador failing to forward a
434 ;; message... it reports it back to the hive
435 (*failed-forward* hive-handle-failed-forward)
436 (*cleanup-all* hive-handle-cleanup-all))))
438 (define-method (hive-handle-failed-forward (hive <hive>) message)
439 "Handle an ambassador failing to forward a message"
442 (define-method (hive-handle-cleanup-all (hive <hive>) message)
443 "Send a message to all actors in our registry to clean themselves up."
444 ;; Unfortunately we have to do this hack and run over the list
445 ;; twice, because hash-for-each would result in an unrewindable
448 (hash-map->list (lambda (actor-id actor) actor-id)
449 (hive-actor-registry hive)))
450 (for-each (lambda (actor-id)
451 (<- actor-id '*cleanup*))
454 (define* (make-hive #:key hive-id)
455 (let ((hive (make <hive>
458 (big-random-number-string))))))
459 ;; Set the hive's actor reference to itself
460 (set! (actor-hive hive) hive)
461 ;; Register the actor with itself
462 (hive-register-actor! hive hive)
465 (define-method (hive-id (hive <hive>))
466 (actor-id-hive hive))
468 (define-method (hive-gen-actor-id (hive <hive>) cookie)
469 (make-address (if cookie
470 (string-append cookie ":" (big-random-number-string))
471 (big-random-number-string))
474 (define-method (hive-gen-message-id (hive <hive>))
475 "Generate a message id using HIVE's message id generator"
476 ((hive-msg-id-generator hive)))
478 (define-method (hive-resolve-local-actor (hive <hive>) actor-address)
479 (hash-ref (hive-actor-registry hive) actor-address))
481 (define-method (hive-resolve-ambassador (hive <hive>) ambassador-address)
482 (hash-ref (hive-ambassadors hive) ambassador-address))
484 (define-method (make-forward-request (hive <hive>) (ambassador <actor>) message)
485 (make-message (hive-gen-message-id hive) (actor-id ambassador)
486 ;; If we make the hive not an actor, we could either switch this
487 ;; to #f or to the original actor...?
488 ;; Maybe some more thinking should be done on what should
489 ;; happen in case of failure to forward? Handling ambassador failures
490 ;; seems like the primary motivation for the hive remaining an actor.
493 `((original . ,message))))
495 (define-method (hive-reply-with-error (hive <hive>) original-message
496 error-key error-args)
497 ;; We only supply the error-args if the original sender is on the same hive
498 (define (orig-actor-on-same-hive?)
499 (equal? (hive-id hive)
500 (address-hive-id (message-from original-message))))
501 (set-message-replied! original-message #t)
502 (let* ((new-message-body
503 (if (orig-actor-on-same-hive?)
504 `(#:original-message ,original-message
505 #:error-key ,error-key
506 #:error-args ,error-args)
507 `(#:original-message ,original-message
508 #:error-key ,error-key)))
509 (new-message (make-message (hive-gen-message-id hive)
510 (message-from original-message)
511 (actor-id hive) '*error*
513 #:in-reply-to (message-id original-message))))
514 ;; We only return a thunk, rather than run 8sync here, because if
515 ;; we ran 8sync in the middle of a catch we'd end up with an
516 ;; unresumable continuation.
517 (lambda () (hive-process-message hive new-message))))
519 (define-record-type <waiting-on-reply>
520 (make-waiting-on-reply actor-id kont send-options)
522 (actor-id waiting-on-reply-actor-id)
523 (kont waiting-on-reply-kont)
524 (send-options waiting-on-reply-send-options))
527 (define-method (hive-process-message (hive <hive>) message)
528 "Handle one message, or forward it via an ambassador"
529 (define (maybe-autoreply actor)
530 ;; Possibly autoreply
531 (if (message-needs-reply? message)
532 (<-auto-reply actor message)))
534 (define (resolve-actor-to)
535 "Get the actor the message was aimed at"
536 (let ((actor (hive-resolve-local-actor hive (message-to message))))
538 (throw 'actor-not-found
539 (format #f "Message ~a from ~a directed to nonexistant actor ~a"
541 (address->string (message-from message))
542 (address->string (message-to message)))
546 (define (call-catching-coroutine thunk)
547 (define queued-error-handling-thunk #f)
548 (define (call-catching-errors)
549 ;; TODO: maybe parameterize (or attach to hive) and use
550 ;; maybe-catch-all from agenda.scm
551 ;; @@: Why not just use with-throw-handler and let the catch
552 ;; happen at the agenda? That's what we used to do, but
553 ;; it ended up with a SIGABRT. See:
554 ;; http://lists.gnu.org/archive/html/bug-guile/2016-05/msg00003.html
557 ;; In the actor model, we don't totally crash on errors.
559 ;; If an error happens, we raise it
561 (if (message-needs-reply? message)
562 ;; If the message is waiting on a reply, let them know
563 ;; something went wrong.
564 ;; However, we have to do it outside of this catch
565 ;; routine, or we'll end up in an unrewindable continuation
567 (set! queued-error-handling-thunk
568 (hive-reply-with-error hive message key args)))
569 ;; print error message
570 (apply print-error-and-continue key args)))
571 ;; @@: This is a kludge. See above for why.
572 (if queued-error-handling-thunk
573 (8sync (queued-error-handling-thunk))))
574 (call-with-prompt (hive-prompt hive)
576 (lambda (kont actor message send-options)
577 ;; Register the coroutine
578 (hash-set! (hive-waiting-coroutines hive)
580 (make-waiting-on-reply
581 (actor-id actor) kont send-options))
582 ;; Send off the message
583 (8sync (hive-process-message hive message)))))
585 (define (process-local-message)
586 (let ((actor (resolve-actor-to)))
587 (call-catching-coroutine
589 (define message-handler (actor-message-handler actor))
590 ;; @@: Should a more general error handling happen here?
591 (parameterize ((%current-actor actor))
593 (message-handler actor message)))
594 (maybe-autoreply actor)
595 ;; Returning result allows actors to possibly make a run-request
596 ;; at the end of handling a message.
597 ;; ... We do want that, right?
600 (define (resume-waiting-coroutine)
601 (case (message-action message)
602 ;; standard reply / auto-reply
603 ((*reply* *auto-reply* *error*)
604 (call-catching-coroutine
606 (match (hash-remove! (hive-waiting-coroutines hive)
607 (message-in-reply-to message))
609 (if (not (equal? (message-to message)
610 (waiting-on-reply-actor-id waiting)))
611 (throw 'resuming-to-wrong-actor
612 "Attempted to resume a coroutine to the wrong actor!"
613 #:expected-actor-id (message-to message)
614 #:got-actor-id (waiting-on-reply-actor-id waiting)
616 (let* (;; @@: How should we resolve resuming coroutines to actors who are
618 (actor (resolve-actor-to))
619 (kont (waiting-on-reply-kont waiting))
620 (result (kont message)))
621 (maybe-autoreply actor)
623 (#f (throw 'no-waiting-coroutine
624 "message in-reply-to tries to resume nonexistent coroutine"
626 ;; Unhandled action for a reply!
628 (throw 'hive-unresumable-coroutine
629 "Won't resume coroutine, nonsense action on reply message"
630 #:action (message-action message)
631 #:message message))))
633 (define (process-remote-message)
634 ;; Find the ambassador
635 (let* ((remote-hive-id (hive-id (message-to message)))
636 (ambassador (hive-resolve-ambassador remote-hive-id))
637 (message-handler (actor-message-handler ambassador))
638 (forward-request (make-forward-request hive ambassador message)))
639 (message-handler ambassador forward-request)))
641 (let ((to (message-to message)))
642 ;; This seems to be an easy mistake to make, so check that addressing
645 (throw 'missing-addressee
646 "`to' field is missing on message"
648 (if (hive-actor-local? hive to)
649 (if (message-in-reply-to message)
650 (resume-waiting-coroutine)
651 (process-local-message))
652 (process-remote-message))))
654 (define-method (hive-actor-local? (hive <hive>) address)
655 (equal? (hive-id hive) (address-hive-id address)))
657 (define-method (hive-register-actor! (hive <hive>) (actor <actor>))
658 (hash-set! (hive-actor-registry hive) (actor-id actor) actor))
660 (define-method (%hive-create-actor (hive <hive>) actor-class
662 "Actual method called by hive-create-actor.
664 Since this is a define-method it can't accept fancy define* arguments,
665 so this gets called from the nicer hive-create-actor interface. See
666 that method for documentation."
667 (let* ((actor-id (hive-gen-actor-id hive id-cookie))
668 (actor (apply make actor-class
672 (hive-register-actor! hive actor)
673 ;; return the actor id
676 (define* (hive-create-actor hive actor-class #:rest init)
677 "Create an actor on HIVE using ACTOR-CLASS passing in INIT args"
678 (%hive-create-actor hive actor-class
679 init (symbol->string (class-name actor-class))))
681 (define* (hive-create-actor* hive actor-class id-cookie #:rest init)
682 "Create an actor, but also allow customizing a 'cookie' added to the id
684 (%hive-create-actor hive actor-class
687 (define (call-with-message message proc)
688 "Applies message body arguments into procedure, with message as first
689 argument. Similar to call-with-values in concept."
690 (apply proc message (message-body message)))
692 ;; (msg-receive (<- bar baz)
696 ;; Emacs: (put 'msg-receive 'scheme-indent-function 2)
698 ;; @@: Or receive-msg or receieve-message or??
699 (define-syntax-rule (msg-receive arglist message body ...)
700 "Call body with arglist (which can accept arguments like lambda*)
701 applied from the message-body of message."
702 (call-with-message message
706 (define (msg-val message)
707 "Retrieve the first value from the message-body of message.
708 Like single value return from a procedure call. Probably the most
709 common case when waiting on a reply from some action invocation."
710 (call-with-message message
711 (lambda (_ val) val)))
714 ;;; Various API methods for actors to interact with the system
715 ;;; ==========================================================
717 ;; TODO: move send-message and friends here...?
719 (define* (create-actor from-actor actor-class #:rest init)
720 "Create an instance of actor-class. Return the new actor's id.
722 This is the method actors should call directly (unless they want
723 to supply an id-cookie, in which case they should use
725 (%hive-create-actor (actor-hive from-actor) actor-class
729 (define* (create-actor* from-actor actor-class id-cookie #:rest init)
730 "Create an instance of actor-class. Return the new actor's id.
732 Like create-actor, but permits supplying an id-cookie."
733 (%hive-create-actor (actor-hive from-actor) actor-class
737 (define* (self-destruct actor #:key (cleanup #t))
738 "Remove an actor from the hive.
740 Unless #:cleanup is set to #f, this will first have the actor handle
741 its '*cleanup* action handler."
743 (<-wait (actor-id actor) '*cleanup*))
744 (hash-remove! (hive-actor-registry (actor-hive actor))
749 ;;; 8sync bootstrap utilities
750 ;;; =========================
752 (define* (run-hive hive initial-tasks
754 "Start up an agenda and run HIVE in it with INITIAL-TASKS."
758 (let* ((queue (list->q initial-tasks))
759 (agenda (make-agenda #:pre-unwind-handler print-error-and-continue
761 (run-agenda agenda)))
765 (run-hive-cleanup hive)))))
767 (define (run-hive-cleanup hive)
768 (let ((queue (list->q (list (bootstrap-message hive (actor-id hive)
771 (make-agenda #:queue queue))))
773 (define (bootstrap-message hive to-id action . message-body-args)
775 (apply <-* `(#:actor ,hive) to-id action message-body-args)))
779 ;;; Basic readers / writers
780 ;;; =======================
782 (define (serialize-message message)
783 "Serialize a message for read/write"
787 (message-from message)
788 (message-action message)
789 (message-body message)
790 (message-in-reply-to message)
791 (message-wants-reply message)
792 (message-replied message)))
794 (define* (write-message message #:optional (port (current-output-port)))
795 "Write out a message to a port for easy reading later.
797 Note that if a sub-value can't be easily written to something
798 Guile's `read' procedure knows how to read, this doesn't do anything
799 to improve that. You'll need a better serializer for that.."
800 (write (serialize-message message) port))
802 (define (serialize-message-pretty message)
803 "Serialize a message in a way that's easy for humans to read."
805 (id ,(message-id message))
806 (to ,(message-to message))
807 (from ,(message-from message))
808 (action ,(message-action message))
809 (body ,(message-body message))
810 (in-reply-to ,(message-in-reply-to message))
811 (wants-reply ,(message-wants-reply message))
812 (replied ,(message-replied message))))
814 (define (pprint-message message)
815 "Pretty print a message."
816 (pretty-print (serialize-message-pretty message)))
818 (define* (read-message #:optional (port (current-input-port)))
819 "Read a message serialized via serialize-message from PORT"
821 ((id to from action body in-reply-to wants-reply replied)
823 id to from action body
824 in-reply-to wants-reply replied))
826 (throw 'message-read-bad-structure
827 "Could not read message from structure"
830 (define (read-message-from-string message-str)
831 "Read message from MESSAGE-STR"
832 (with-input-from-string message-str
834 (read-message (current-input-port)))))