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