X-Git-Url: https://jxself.org/git/?p=8sync.git;a=blobdiff_plain;f=eightsync%2Fagenda.scm;h=9f54e17aa06ca2faf76c652de922e803bfb027af;hp=adbd0c688f402def34b35cf01ef7db7ace697cee;hb=5a32dfc9d2b5a5b873d57ecdbf29f68a136cb0b0;hpb=77ac93255544d74b0217e75de4f8a23361397f28 diff --git a/eightsync/agenda.scm b/eightsync/agenda.scm index adbd0c6..9f54e17 100644 --- a/eightsync/agenda.scm +++ b/eightsync/agenda.scm @@ -50,7 +50,7 @@ schedule-segments-split schedule-extract-until! add-segments-contents-to-queue! - %sync 8sync + %8sync make-run-request run-request? @@ -61,11 +61,20 @@ port-request-port port-request-read port-request-write port-request-except - run-it wrap run run-at run-delay + run-it wrap wrap-apply run run-at run-delay %port-request %run %run-at %run-delay - 8port-request 8run 8run-at 8run-delay + catch-8sync catch-%8sync + + ;; used for introspecting the error, but a method for making + ;; is not exposed + wrapped-exception? + wrapped-exception-key wrapped-exception-args + wrapped-exception-stacks + + print-error-and-continue + %current-agenda start-agenda agenda-run-once)) @@ -93,7 +102,7 @@ (define-immutable-record-type (make-agenda-intern queue prompt-tag read-port-map write-port-map except-port-map - schedule time) + schedule time catch-handler pre-unwind-handler) agenda? (queue agenda-queue) (prompt-tag agenda-prompt-tag) @@ -101,7 +110,9 @@ (write-port-map agenda-write-port-map) (except-port-map agenda-except-port-map) (schedule agenda-schedule) - (time agenda-time)) + (time agenda-time) + (catch-handler agenda-catch-handler) + (pre-unwind-handler agenda-pre-unwind-handler)) (define (make-async-prompt-tag) "Make an async prompt tag for an agenda. @@ -116,12 +127,15 @@ Generally done automatically for the user through (make-agenda)." (write-port-map (make-hash-table)) (except-port-map (make-hash-table)) (schedule (make-schedule)) - (time (gettimeofday))) + (time (gettimeofday)) + (catch-handler #f) + (pre-unwind-handler #f)) ;; TODO: document arguments "Make a fresh agenda." (make-agenda-intern queue prompt read-port-map write-port-map except-port-map - schedule time)) + schedule time + catch-handler pre-unwind-handler)) (define (current-agenda-prompt) "Get the prompt for the current agenda; signal an error if there isn't one." @@ -382,6 +396,12 @@ Will produce (0 . 0) instead of a negative number, if needed." (lambda () body ...)) +(define-syntax-rule (wrap-apply body) + "Wrap possibly multi-value function in a procedure, applies all arguments" + (lambda args + (apply body args))) + + ;; @@: Do we really want `body ...' here? ;; what about just `body'? (define-syntax-rule (run body ...) @@ -422,59 +442,26 @@ Will produce (0 . 0) instead of a negative number, if needed." ;;; Asynchronous escape to run things ;;; ================================= -;; The future's in futures - -(define (make-future call-first on-success on-fail on-error) - ;; TODO: add error stuff here - (lambda () - (let ((call-result (call-first))) - ;; queue up calling the - (run (on-success call-result))))) - (define (agenda-on-error agenda) (const #f)) (define (agenda-on-fail agenda) (const #f)) -(define* (request-future call-first on-success - #:key - (agenda (%current-agenda)) - (on-fail (agenda-on-fail agenda)) - (on-error (agenda-on-error agenda)) - (when #f)) - ;; TODO: error handling - ;; do we need some distinction between expected, catchable errors, - ;; and unexpected, uncatchable ones? Probably...? - (make-run-request - (make-future call-first on-success on-fail on-error) - when)) - -(define-syntax-rule (%sync async-request) +(define-syntax-rule (%8sync async-request) "Run BODY asynchronously at a prompt, passing args to make-future. -Pronounced `eight-sync' despite the spelling. - -%sync was chosen because (async) was already taken and could lead to -errors, and this version of asynchronous code uses a prompt, so the `a' -character becomes a `%' prompt! :) - -The % and 8 characters kind of look similar... hence this library's -name! (That, and the pun 'eight-synchronous' programming.) -There are 8sync aliases if you prefer that name." - (abort-to-prompt (current-agenda-prompt) - async-request)) - -(define-syntax-rule (8sync args ...) - "Alias for %sync" - (%sync args ...)) +Runs things asynchronously (8synchronously?)" + (propagate-%async-exceptions + (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) @@ -485,19 +472,65 @@ return the wrong thing via (8sync) and trip themselves up." ;; TODO: deliver more helpful errors depending on what the user ;; returned (_ (throw 'invalid-async-request - "Invalid request passed back via an (%sync) procedure." + "Invalid request passed back via an (%8sync) procedure." async-request)))) +(define-record-type + (make-wrapped-exception key args stacks) + wrapped-exception? + (key wrapped-exception-key) + (args wrapped-exception-args) + (stacks wrapped-exception-stacks)) + +(define-syntax-rule (propagate-%async-exceptions body) + (let ((body-result body)) + (if (wrapped-exception? body-result) + (throw '8sync-caught-error + (wrapped-exception-key body-result) + (wrapped-exception-args body-result) + (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 - (begin body ...))) + ;; 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) @@ -517,11 +550,21 @@ return the wrong thing via (8sync) and trip themselves up." (lambda () body ...))))) -;; Aliases -(define-syntax-rule (8run args ...) (%run args ...)) -(define-syntax-rule (8run-at args ...) (%run-at args ...)) -(define-syntax-rule (8run-delay args ...) (%run-delay args ...)) -(define-syntax-rule (8port-request args ...) (%port-request args ...)) +(define-syntax-rule (catch-8sync exp (handler-key handler) ...) + (catch '8sync-caught-error + (lambda () + exp) + (lambda (_ orig-key orig-args orig-stacks) + (cond + ((or (eq? handler-key #t) + (eq? orig-key handler-key)) + (apply handler orig-stacks orig-args)) ... + (else (raise '8sync-caught-error + orig-key orig-args orig-stacks)))))) + +;; Alias...? +(define-syntax-rule (catch-%8sync rest ...) + (catch-8sync rest ...)) @@ -655,6 +698,25 @@ return the wrong thing via (8sync) and trip themselves up." (agenda-queue agenda)) (loop agenda)))))) +(define (print-error-and-continue . args) + "Frequently used as pre-unwind-handler for agenda" + (format (current-error-port) "\n*** Caught exception with arguments: ~s ***\n" + args) + (display-backtrace (make-stack #t 1 0) + (current-error-port)) + (newline (current-error-port))) + +(define-syntax-rule (maybe-catch-all (catch-handler pre-unwind-handler) + body ...) + (if (or catch-handler pre-unwind-handler) + (catch + #t + (lambda () + body ...) + (or catch-handler (lambda _ #f)) + (or pre-unwind-handler (lambda _ #f))) + (begin body ...))) + (define (agenda-run-once agenda) "Run once through the agenda, and produce a new agenda based on the results" @@ -663,7 +725,10 @@ based on the results" (agenda-prompt-tag agenda) (lambda () (parameterize ((%current-agenda agenda)) - (proc))) + (maybe-catch-all + ((agenda-catch-handler agenda) + (agenda-pre-unwind-handler agenda)) + (proc)))) (lambda (kont async-request) (setup-async-request kont async-request))))