Prepare for Concurrency lecture

Author: s-macke

go.mod

@@ -1,8 +1,6 @@
 module github.com/s-macke/concepts-of-programming-languages
 
-go 1.22.0
-
-toolchain go1.23.0
+go 1.23
 
 require (
 	github.com/antlr/antlr4/runtime/Go/antlr v0.0.0-20210930093333-01de314d7883

src/concurrent/channels/philosophers/build.sh

@@ -1,23 +1,15 @@
 package main
 
-import (
-	"time"
-)
-
 func main() {
-
-	var COUNT = 5
+	nbrOfSeats := 5
 
 	// start table for 5
-	table := NewTable(COUNT)
+	table := NewTable(nbrOfSeats)
 
 	// start philosophers
-	for i := 0; i < COUNT; i++ {
+	for i := 0; i < nbrOfSeats; i++ {
 		philosopher := NewPhilosopher(i, table)
 		go philosopher.run()
 	}
-	go table.run()
-
-	// wait 1 millisecond --> check output
-	time.Sleep(10 * time.Second)
+	table.run()
 }

src/concurrent/channels/philosophers/main.go

@@ -49,15 +49,14 @@ func (p *Philosopher) takeForks() {
 	// try to get forks from table
 	gotForks := false
 	for !gotForks {
-		p.table.getTakeChannel() <- p.id
-		gotForks = <-p.table.getReservedChannel(p.id)
+		gotForks = p.table.askForFork(p.id)
 	}
 }
 
 // Put forks by channeling our id to the table. The table is responsible for the put logic.
 func (p *Philosopher) putForks() {
 	fmt.Printf("Philosopher #%d puts down forks\n", p.id)
-	p.table.getPutChannel() <- p.id
+	p.table.PutFork(p.id)
 }
 
 // Eating.

src/concurrent/channels/philosophers/philosophers.go

@@ -35,21 +35,29 @@ type Table struct {
 
 // NewTable constructs a table with n seats.
 func NewTable(nbrOfSeats int) *Table {
-	table := &Table{}
-
-	// initialize channels
-	table.takeCh = make(chan int)
-	table.putCh = make(chan int)
+	table := &Table{
+		nbrOfSeats: nbrOfSeats,
+		forkInUse:  make([]bool, nbrOfSeats),
+		takeCh:     make(chan int),
+		putCh:      make(chan int),
+	}
 
 	table.reservedCh = make([]chan bool, nbrOfSeats)
 	for i := 0; i < nbrOfSeats; i++ {
 		table.reservedCh[i] = make(chan bool)
 	}
-	table.forkInUse = make([]bool, nbrOfSeats)
-	table.nbrOfSeats = nbrOfSeats
 	return table
 }
 
+func (t *Table) askForFork(id int) bool {
+	t.takeCh <- id
+	return <-t.reservedCh[id]
+}
+
+func (t *Table) PutFork(id int) {
+	t.putCh <- id
+}
+
 // Function run() contains the main loop for assigning forks and starting philosophers.
 func (t *Table) run() {
 
@@ -75,15 +83,3 @@ func (t *Table) run() {
 		}
 	}
 }
-
-func (t *Table) getTakeChannel() chan int {
-	return t.takeCh
-}
-
-func (t *Table) getPutChannel() chan int {
-	return t.putCh
-}
-
-func (t *Table) getReservedChannel(id int) chan bool {
-	return t.reservedCh[id]
-}