Merge pull request #2 from oplS17projects/mango

Mango

1 files changed, 75 insertions, 0 deletions

diff --git a/tests/gui/concurrentreadandprint.rkt b/tests/gui/concurrentreadandprint.rkt
new file mode 100644
index 0000000..95d02c1
--- /dev/null
+++ b/tests/gui/concurrentreadandprint.rkt
@@ -0,0 +1,75 @@
+#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")