+ (prompt (make-prompt-tag))
+ (read-port-map (make-hash-table))
+ (write-port-map (make-hash-table))
+ (except-port-map (make-hash-table))
+ (schedule (make-schedule))
+ (time (gettimeofday)))
+ (make-agenda-intern queue prompt
+ read-port-map write-port-map except-port-map
+ schedule time))
+
+
+\f
+;;; Schedule
+;;; ========
+
+;;; This is where we handle timed events for the future
+
+;; This section totally borrows from the ideas in SICP
+;; <3 <3 <3
+
+;; NOTE: time is a cons of (seconds . microseconds)
+
+(define-record-type <time-segment>
+ (make-time-segment-intern time queue)
+ time-segment?
+ (time time-segment-time)
+ (queue time-segment-queue))
+
+(define (time-segment-right-format time)
+ (match time
+ ;; time is already a cons of second and microsecnd
+ (((? integer? s) . (? integer? u)) time)
+ ;; time was just an integer (just the second)
+ ((? integer? _) (cons time 0))
+ (_ (throw 'invalid-time "Invalid time" time))))
+
+(define* (make-time-segment time #:optional (queue (make-q)))
+ (make-time-segment-intern time queue))
+
+(define (time-< time1 time2)
+ (cond ((< (car time1)
+ (car time2))
+ #t)
+ ((and (= (car time1)
+ (car time2))
+ (< (cdr time1)
+ (cdr time2)))
+ #t)
+ (else #f)))
+
+(define (time-= time1 time2)
+ (and (= (car time1) (car time2))
+ (= (cdr time1) (cdr time2))))
+
+(define (time-<= time1 time2)
+ (or (time-< time1 time2)
+ (time-= time1 time2)))
+
+
+(define-record-type <time-delta>
+ (make-time-delta-intern sec usec)
+ time-delta?
+ (sec time-delta-sec)
+ (usec time-delta-usec))
+
+(define* (make-time-delta sec #:optional usec)
+ (make-time-delta-intern sec (or usec 0)))
+
+(define tdelta make-time-delta)
+
+(define (time-+ time time-delta)
+ (cons (+ (car time) (time-delta-sec time-delta))
+ (+ (cdr time) (time-delta-usec time-delta))))
+
+
+(define-record-type <schedule>
+ (make-schedule-intern segments)
+ schedule?
+ (segments schedule-segments set-schedule-segments!))
+
+(define* (make-schedule #:optional segments)
+ (make-schedule-intern (or segments '())))
+
+(define (schedule-soonest-time schedule)
+ "Return a cons of (sec . usec) for next time segement, or #f if none"
+ (let ((segments (schedule-segments schedule)))
+ (if (eq? segments '())
+ #f
+ (time-segment-time (car segments)))))
+
+;; TODO: This code is reasonably easy to read but it
+;; mutates AND is worst case of O(n) in both space and time :(
+;; but at least it'll be reasonably easy to refactor to
+;; a more functional setup?
+(define (schedule-add! schedule time proc)
+ (let ((time (time-segment-right-format time)))
+ (define (new-time-segment)
+ (let ((new-segment
+ (make-time-segment time)))
+ (enq! (time-segment-queue new-segment) proc)
+ new-segment))
+ (define (loop segments)
+ (define (segment-equals-time? segment)
+ (time-= time (time-segment-time segment)))
+
+ (define (segment-more-than-time? segment)
+ (time-< time (time-segment-time segment)))
+
+ ;; We could switch this out to be more mutate'y
+ ;; and avoid the O(n) of space... is that over-optimizing?
+ (match segments
+ ;; If we're at the end of the list, time to make a new
+ ;; segment...
+ ('() (cons (new-time-segment) '()))
+ ;; If the segment's time is exactly our time, good news
+ ;; everyone! Let's append our stuff to its queue
+ (((? segment-equals-time? first) rest ...)
+ (enq! (time-segment-queue first) proc)
+ segments)
+ ;; If the first segment is more than our time,
+ ;; ours belongs before this one, so add it and
+ ;; start consing our way back
+ (((? segment-more-than-time? first) rest ...)
+ (cons (new-time-segment) segments))
+ ;; Otherwise, build up recursive result
+ ((first rest ... )
+ (cons first (loop rest)))))
+ (set-schedule-segments!
+ schedule
+ (loop (schedule-segments schedule)))))
+
+(define (schedule-empty? schedule)
+ (eq? (schedule-segments schedule) '()))
+
+(define (schedule-segments-split schedule time)
+ "Does a multiple value return of time segments before/at and after TIME"
+ (let ((time (time-segment-right-format time)))
+ (define (segment-is-now? segment)
+ (time-= (time-segment-time segment) time))
+ (define (segment-is-before-now? segment)
+ (time-< (time-segment-time segment) time))
+
+ (let loop ((segments-before '())
+ (segments-left (schedule-segments schedule)))
+ (match segments-left
+ ;; end of the line, return
+ ('()
+ (values (reverse segments-before) '()))
+
+ ;; It's right now, so time to stop, but include this one in before
+ ;; but otherwise return
+ (((? segment-is-now? first) rest ...)
+ (values (reverse (cons first segments-before)) rest))
+
+ ;; This is prior or at now, so add it and keep going
+ (((? segment-is-before-now? first) rest ...)
+ (loop (cons first segments-before) rest))
+
+ ;; Otherwise it's past now, just return what we have
+ (segments-after
+ (values segments-before segments-after))))))
+
+(define (schedule-extract-until! schedule time)
+ "Extract all segments until TIME from SCHEDULE, and pop old segments off"
+ (receive (segments-before segments-after)
+ (schedule-segments-split schedule time)
+ (set-schedule-segments! schedule segments-after)
+ segments-before))
+
+(define (add-segments-contents-to-queue! segments queue)
+ (for-each
+ (lambda (segment)
+ (let ((seg-queue (time-segment-queue segment)))
+ (while (not (q-empty? seg-queue))
+ (enq! queue (deq! seg-queue)))))
+ segments))
+
+
+\f
+;;; Port handling
+;;; =============
+
+(define (make-port-mapping)
+ (make-hash-table))
+
+(define* (port-mapping-set! port-mapping port #:optional read write except)
+ "Sets port-mapping for reader / writer / exception handlers"
+ (if (not (or read write except))
+ (throw 'no-handlers-given "No handlers given for port" port))
+ (hashq-set! port-mapping port
+ `#(,read ,write ,except)))
+
+(define (port-mapping-remove! port-mapping port)
+ (hashq-remove! port-mapping port))
+
+;; TODO: This is O(n), I'm pretty sure :\
+;; ... it might be worthwhile for us to have a
+;; port-mapping record that keeps a count of how many
+;; handlers (maybe via a promise?)
+(define (port-mapping-empty? port-mapping)
+ "Is this port mapping empty?"
+ (eq? (hash-count (const #t) port-mapping) 0))
+
+(define (port-mapping-non-empty? port-mapping)
+ "Whether this port-mapping contains any elements"
+ (not (port-mapping-empty? port-mapping)))
+
+
+\f
+;;; Request to run stuff
+;;; ====================
+
+(define-record-type <run-request>
+ (make-run-request proc when)
+ run-request?
+ (proc run-request-proc)
+ (when run-request-when))
+
+(define* (run proc #:optional when)
+ (make-run-request proc when))
+
+(define-syntax-rule (wrap body ...)
+ (lambda ()
+ body ...))
+
+(define-syntax-rule (run-wrap body ...)
+ (run (wrap body ...)))
+
+(define-syntax-rule (run-wrap-at body ... when)
+ (run (wrap body ...) when))
+
+\f
+;;; Execution of agenda, and current agenda
+;;; =======================================