45 lines
1.4 KiB
Racket
45 lines
1.4 KiB
Racket
#lang racket/base
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;; Trivial demonstration of an os2.rkt virtual machine.
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(require "os2.rkt")
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(require racket/pretty)
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(define (super-alarm msecs)
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(wrap-evt (alarm-evt msecs) (lambda (_) (current-inexact-milliseconds))))
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(define (sleep n k)
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(transition k
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(role (topic-subscriber (super-alarm (+ (current-inexact-milliseconds) n)))
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#:state k
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#:id id
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#:on-ready (begin (write `(ready ,id)) (newline) k)
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[now (extend-transition (k) (delete-role id))])))
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(define (example-process delay)
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(write `(sleeping for ,delay milliseconds))
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(newline)
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(sleep delay (lambda ()
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(if (> delay 1500)
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(error 'example-process "Oh noes!")
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(begin (write `(awoke after ,delay milliseconds))
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(newline)
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(transition 'no-state (kill)))))))
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(define spy
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(lambda (spy-pid)
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(define (hs label)
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(define ((w kind) . args) (write `(,label ,kind ,@args)) (newline) values)
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(handlers (w 'presence)
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(w 'absence)
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(w 'message)))
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(transition 'spy-state
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(add-role (topic-publisher (wild) #:virtual? #t) (hs 'subscriber->publisher))
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(add-role (topic-subscriber (wild) #:virtual? #t) (hs 'publisher->subscriber)))))
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(ground-vm (lambda (boot-pid)
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(transition 'no-state
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(spawn spy)
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(spawn (lambda (pid) (example-process 1000)))
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(spawn (lambda (pid) (example-process 2000)))
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(kill))))
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