76 lines
2.3 KiB
Racket
76 lines
2.3 KiB
Racket
#lang racket
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(require math/base) ;; for random number generation
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;; a proof of concept
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;; one thread waits for input
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;; another displays messages in the background
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;; create custodian for managing all resources
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;; so we can shutdown everything at once
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;(define guard (make-custodian (current-custodian)))
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;(current-custodian guard)
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;; reads values continously from stdin and redisplays them
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(define (read-loop)
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(display (read-line))
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(display "\n")
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(read-loop)
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)
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(define input-prompt "input: ")
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(define output-prompt "output: ")
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;; prompt for username and bind to a variable username
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(display "What's your name?\n")
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(define username (read-line))
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(define usernamei (string-append username ": ")) ;; make username appear nicer in a prompt
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(define fair (make-semaphore 1))
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;; intelligent read, quits when user types in "quit"
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(define (read-loop-i)
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;(semaphore-wait fair)
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(display usernamei)
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(define input (read-line))
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;; do something over here with input maybe send it out
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;; Tests input if its a quit then kills all threads
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;; An if would be better here tbh
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(cond ((string=? input "quit") (begin (kill-thread a)
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(kill-thread t))))
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(display (string-append output-prompt input "\n"))
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;(semaphore-post fair)
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(read-loop-i)
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)
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;; print hello world continously
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;; "(hello-world)" can be executed as part of background thread
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;; that prints in the event there is something in the input port
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(define (hello-world)
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(sleep (random-integer 0 15)) ;; sleep between 0 and 15 seconds to simulate coms
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;; with server
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;(semaphore-wait fair)
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;; we will retrieve the line printed below from the server
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;; at this time we simulate the input from different users
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(define what-to-print (random-integer 0 2))
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(if (= what-to-print 0)
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(display "Doug: What's up, up?\n")
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(display "Fred: Looking good, good!\n"))
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;(semaphore-post fair)
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(hello-world))
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(define t (thread (lambda ()
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(read-loop-i))))
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(define a (thread (lambda ()
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(hello-world))))
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(thread-wait t) ;; returns prompt back to drracket
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;; below doesn't execute
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; (sleep 10)
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; (kill-thread t)
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; (define a (thread (display "hello world!\n")))
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; (display "John: hello soso\n")
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; (display "Emmanuel: cumbaya!!!!\n")
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