June 2018 Update

Task/Dining-philosophers/Common-Lisp/dining-philosophers-2.lisp

@@ -0,0 +1,49 @@
+(ql:quickload '(:stmx :bordeaux-threads))
+
+(defpackage :dining-philosophers
+  (:use :cl))
+
+(in-package :dining-philosophers)
+
+(defstruct philosopher
+  name
+  left-fork
+  right-fork)
+
+(defparameter *philosophers* '("Aristotle" "Kant" "Spinoza" "Marx" "Russell"))
+(defparameter *eating-max* 5.0)
+(defparameter *thinking-max* 5.0)
+(defvar *log-lock* (bt:make-lock))
+(defvar *running* nil)
+
+(defun print-log (name status)
+  (bt:with-lock-held (*log-lock*)
+    (format t "~a is ~a~%" name status)))
+
+(defun philosopher-cycle (philosopher)
+  "Continously atomically grab and return the left and right forks of the given PHILOSOPHER."
+  (with-slots (name left-fork right-fork) philosopher
+    (loop while *running*
+       do
+         (print-log name "hungry")
+         (stmx:atomic
+          (stmx.util:take left-fork)
+          (stmx.util:take right-fork))
+         (print-log name "eating")
+         (sleep (random *eating-max*))
+         (stmx:atomic
+          (stmx.util:put left-fork t)
+          (stmx.util:put right-fork t))
+         (print-log name "thinking")
+         (sleep (random *thinking-max*)))))
+
+(defun scenario ()
+  (let ((forks (loop repeat (length *philosophers*) collect (stmx.util:tcell t))))
+    (setf *running* t)
+    (loop for name in *philosophers*
+       for left-fork in forks
+       for right-fork in (append (cdr forks) (list (car forks)))
+       do (let ((philosopher (make-philosopher :name name :left-fork left-fork :right-fork right-fork)))
+            (bt:make-thread (lambda () (philosopher-cycle philosopher))
+                            :initial-bindings (cons (cons '*standard-output* *standard-output*)
+                                                    bt:*default-special-bindings*))))))

Task/Dining-philosophers/Common-Lisp/dining-philosophers-3.lisp

@@ -0,0 +1,44 @@
+DINING-PHILOSOPHERS> (scenario)
+Aristotle is hungry
+Aristotle is eating
+Kant is hungry
+Spinoza is hungry
+Spinoza is eating
+Marx is hungry
+NIL
+Russell is hungry
+Aristotle is thinking
+Russell is eating
+Spinoza is thinking
+Kant is eating
+Spinoza is hungry
+Russell is thinking
+Marx is eating
+Kant is thinking
+Aristotle is hungry
+Aristotle is eating
+Marx is thinking
+Spinoza is eating
+Spinoza is thinking
+Marx is hungry
+Marx is eating
+Russell is hungry
+Marx is thinking
+Kant is hungry
+Aristotle is thinking
+Russell is eating
+Kant is eating
+Marx is hungry
+Spinoza is hungry
+Kant is thinking
+Spinoza is eating
+Kant is hungry
+Aristotle is hungry
+Russell is thinking
+Aristotle is eating
+Aristotle is thinking
+Aristotle is hungry
+Aristotle is eating
+Spinoza is thinking
+Marx is eating
+...