;;; 8sync --- Asynchronous programming for Guile
-;;; Copyright (C) 2015 Christopher Allan Webber <cwebber@dustycloud.org>
+;;; Copyright (C) 2015, 2016 Christopher Allan Webber <cwebber@dustycloud.org>
;;;
;;; This file is part of 8sync.
;;;
schedule-segments-split schedule-extract-until!
add-segments-contents-to-queue!
- %8sync
-
<run-request>
make-run-request run-request?
run-request-proc run-request-when
port-request-port
port-request-read port-request-write port-request-except
+ <port-remove-request>
+ make-port-remove-request port-remove-request port-remove-request?
+ port-remove-request-port
+
run-it wrap wrap-apply run run-at run-delay
- %port-request %run %run-at %run-delay
+ 8sync 8sync-delay
+ 8sync-run 8sync-run-at 8sync-run-delay
+ 8sync-port 8sync-port-remove
+ 8sync-nowait
+ 8sleep
- catch-8sync catch-%8sync
+ catch-8sync
;; used for introspecting the error, but a method for making
;; is not exposed
print-error-and-continue
+ stop-on-nothing-to-do
+
%current-agenda
start-agenda agenda-run-once))
(schedule (make-schedule))
(time (gettimeofday))
(catch-handler #f)
- (pre-unwind-handler #f))
+ (pre-unwind-handler print-error-and-continue))
;; TODO: document arguments
"Make a fresh agenda."
(make-agenda-intern queue prompt
(define port-request make-port-request)
+(define-record-type <port-remove-request>
+ (make-port-remove-request port)
+ port-remove-request?
+ (port port-remove-request-port))
+
+(define port-remove-request make-port-remove-request)
+
\f
;;; Asynchronous escape to run things
;;; =================================
-(define-syntax-rule (%8sync async-request)
- "Run BODY asynchronously at a prompt, passing args to make-future.
-
-Runs things asynchronously (8synchronously?)"
- (propagate-%async-exceptions
- (abort-to-prompt (current-agenda-prompt)
- async-request)))
+(define-syntax-rule (8sync-abort-to-prompt async-request)
+ (abort-to-prompt (current-agenda-prompt)
+ async-request))
;; Async port request and run-request meta-requests
(define (make-async-request proc)
"Wrap PROC in an async-request
The purpose of this is to make sure that users don't accidentally
-return the wrong thing via (%8sync) and trip themselves up."
+return the wrong thing via (8sync) and trip themselves up."
(cons '*async-request* proc))
(define (setup-async-request resume-kont async-request)
;; TODO: deliver more helpful errors depending on what the user
;; returned
(_ (throw 'invalid-async-request
- "Invalid request passed back via an (%8sync) procedure."
+ "Invalid request passed back via an (8sync) procedure."
async-request))))
(define-record-type <wrapped-exception>
(wrapped-exception-stacks body-result))
body-result)))
-(define-syntax-rule (%run body ...)
- (%run-at body ... #f))
-
-(define-syntax-rule (%run-at body ... when)
- ;; Send an asynchronous request to apply a continuation to the
- ;; following function, then handle that as a request to the agenda
- (make-async-request
- (lambda (kont)
- ;; We're making a run request
- (make-run-request
- ;; Wrapping the following execution to run...
- (wrap
- ;; Once we get the result from the inner part, we'll resume
- ;; this continuation, but first
- ;; @@: Is this running immediately, or queueing the result
- ;; after evaluation for the next agenda tick? It looks
- ;; like evaluating immediately. Is that what we want?
- (kont
- ;; Any unhandled errors are caught
- (let ((exception-stack #f))
- (catch #t
- ;; Run the actual code the user requested
- (lambda ()
- body ...)
- ;; If something bad happened and we didn't catch it,
- ;; we'll wrap it up in such a way that the continuation
- ;; can address it
- (lambda (key . args)
- (cond
- ((eq? key '8sync-caught-error)
- (match args
- ((orig-key orig-args orig-stacks)
- (make-wrapped-exception
- orig-key orig-args
- (cons exception-stack orig-stacks)))))
- (else
- (make-wrapped-exception key args
- (list exception-stack)))))
- (lambda _
- (set! exception-stack (make-stack #t 1 0)))))))
- when))))
-
-(define-syntax-rule (%run-delay body ... delay-time)
- (%run-at body ... (tdelta delay-time)))
-
-(define-syntax-rule (%port-request add-this-port port-request-args ...)
- (make-async-request
- (lambda (kont)
- (list (make-port-request port-request-args ...)
- (make-run-request kont)))))
-
-;; TODO
-(define-syntax-rule (%run-with-return return body ...)
- (make-async-request
- (lambda (kont)
- (let ((return kont))
- (lambda ()
- body ...)))))
+(define-syntax 8sync
+ (syntax-rules ()
+ "Run BODY asynchronously (8synchronously?) at a prompt, then return.
+
+Possibly specify WHEN as the second argument."
+ ((8sync body)
+ (8sync-run body))
+ ((8sync body when)
+ (8sync-run-at body when))))
+
+(define-syntax-rule (8sync-run body ...)
+ (8sync-run-at body ... #f))
+
+(define-syntax-rule (8sync-run-at body ... when)
+ (propagate-%async-exceptions
+ (8sync-abort-to-prompt
+ ;; Send an asynchronous request to apply a continuation to the
+ ;; following function, then handle that as a request to the agenda
+ (make-async-request
+ (lambda (kont)
+ ;; We're making a run request
+ (make-run-request
+ ;; Wrapping the following execution to run...
+ (wrap
+ ;; Once we get the result from the inner part, we'll resume
+ ;; this continuation, but first
+ ;; @@: Is this running immediately, or queueing the result
+ ;; after evaluation for the next agenda tick? It looks
+ ;; like evaluating immediately. Is that what we want?
+ (kont
+ ;; Any unhandled errors are caught
+ (let ((exception-stack #f))
+ (catch #t
+ ;; Run the actual code the user requested
+ (lambda ()
+ body ...)
+ ;; If something bad happened and we didn't catch it,
+ ;; we'll wrap it up in such a way that the continuation
+ ;; can address it
+ (lambda (key . args)
+ (cond
+ ((eq? key '8sync-caught-error)
+ (match args
+ ((orig-key orig-args orig-stacks)
+ (make-wrapped-exception
+ orig-key orig-args
+ (cons exception-stack orig-stacks)))))
+ (else
+ (make-wrapped-exception key args
+ (list exception-stack)))))
+ (lambda _
+ (set! exception-stack (make-stack #t 1 0)))))))
+ when))))))
+
+(define-syntax-rule (8sync-run-delay body ... delay-time)
+ (8sync-run-at body ... (tdelta delay-time)))
+
+(define-syntax-rule (8sync-delay args ...)
+ (8sync-run-delay args ...))
+
+(define-syntax-rule (8sync-port port port-request-args ...)
+ (8sync-abort-to-prompt
+ (make-async-request
+ (lambda (kont)
+ (list (make-port-request port port-request-args ...)
+ (make-run-request
+ ;; What's with returning #f to kont?
+ ;; Otherwise we sometimes get errors like
+ ;; "Zero values returned to single-valued continuation""
+ (wrap (kont #f)) #f))))))
+
+(define-syntax-rule (8sync-port-remove port)
+ (8sync-abort-to-prompt
+ (make-async-request
+ (lambda (kont)
+ (list (make-port-remove-request port)
+ (make-run-request
+ ;; See comment in 8sync-port
+ (wrap (kont #f)) #f))))))
+
+
+;; TODO: Write (%run-immediately)
+
+(define-syntax-rule (8sync-nowait body)
+ "Run body asynchronously but ignore its result...
+forge ahead in our current function!"
+ (8sync-abort-to-prompt
+ (make-async-request
+ (lambda (kont)
+ (list (make-run-request
+ ;; See comment in 8sync-port
+ (wrap (kont #f)) #f)
+ (make-run-request (lambda () body) #f))))))
(define-syntax-rule (catch-8sync exp (handler-key handler) ...)
(catch '8sync-caught-error
(else (raise '8sync-caught-error
orig-key orig-args orig-stacks))))))
-;; Alias...?
-(define-syntax-rule (catch-%8sync rest ...)
- (catch-8sync rest ...))
+;; This is sugar... and could probably be considerably
+;; simplified and optimized. But whatever.
+(define-syntax-rule (8sleep time)
+ (8sync-delay 'no-op time))
\f
(define %current-agenda (make-parameter #f))
(define (update-agenda-from-select! agenda)
- "Potentially (select) on ports specified in agenda, adding items to queue"
+ "Potentially (select) on ports specified in agenda, adding items to queue.
+
+Also handles sleeping when all we have to do is wait on the schedule."
(define (hash-keys hash)
(hash-map->list (lambda (k v) k) hash))
(define (get-wait-time)
(has-items? agenda-write-port-map)
(has-items? agenda-except-port-map)))
- (if (ports-to-select?)
+ (if (or (ports-to-select?)
+ ;; select doubles as sleep...
+ (not (schedule-empty? (agenda-schedule agenda))))
(update-agenda)
agenda))
"Update an agenda for a port-request"
(define (handle-selector request-selector port-map-selector)
(if (request-selector port-request)
+ ;; @@: Should we remove if #f?
(hash-set! (port-map-selector agenda)
(port-request-port port-request)
(request-selector port-request))))
(handle-selector port-request-except agenda-except-port-map))
+(define (agenda-handle-port-remove-request! agenda port-remove-request)
+ "Update an agenda for a port-remove-request"
+ (let ((port (port-remove-request-port port-remove-request)))
+ (hash-remove! (agenda-read-port-map agenda) port)
+ (hash-remove! (agenda-write-port-map agenda) port)
+ (hash-remove! (agenda-except-port-map agenda) port)))
+
+
+(define (stop-on-nothing-to-do agenda)
+ (and (q-empty? (agenda-queue agenda))
+ (schedule-empty? (agenda-schedule agenda))
+ (= 0 (hash-count (const #t) (agenda-read-port-map agenda)))
+ (= 0 (hash-count (const #t) (agenda-write-port-map agenda)))
+ (= 0 (hash-count (const #t) (agenda-except-port-map agenda)))))
+
+
(define* (start-agenda agenda
- #:key stop-condition
+ #:key
+ ;; @@: Should we make stop-on-nothing-to-do
+ ;; the default stop-condition?
+ (stop-condition stop-on-nothing-to-do)
(get-time gettimeofday)
- (handle-ports update-agenda-from-select!))
+ (handle-ports update-agenda-from-select!)
+ ;; For live hacking madness, etc
+ (post-run-hook #f))
;; TODO: Document fields
"Start up the AGENDA"
(let loop ((agenda agenda))
;; select'ing on ports.
;; We could compose over agenda-run-once and agenda-read-ports
(agenda-run-once agenda)))
+ ;; @@: This relies on mutation at present on the queue, in the rare
+ ;; event it's used. If we ever switch to something more immutable,
+ ;; it should return a new modified agenda instead.
+ (if post-run-hook
+ (post-run-hook agenda))
(if (and stop-condition (stop-condition agenda))
'done
(let* ((agenda
(agenda-queue agenda))
(loop agenda))))))
+
(define (print-error-and-continue key . args)
"Frequently used as pre-unwind-handler for agenda"
(cond
(#f
(enq! next-queue (run-request-proc run-request))))))))
(define (handle-individual result)
+ ;; @@: Could maybe optimize by switching to an explicit cond...
(match result
((? run-request? new-proc)
(enqueue new-proc))
((? port-request? port-request)
(agenda-handle-port-request! agenda port-request))
+ ((? port-remove-request? port-remove-request)
+ (agenda-handle-port-remove-request! agenda port-remove-request))
;; do nothing
(_ #f)))
;; @@: We might support delay-wrapped procedures here