Simple Echo Server

Main.flix

use Abort.abort
import java.io.InputStreamReader
import java.io.PrintWriter
import java.io.BufferedReader
import java.net.Socket
import java.net.ServerSocket
// The main entry point.
def main(): Unit \ {Net, IO, Abort} =
    let port = 8080;
    let serverSocket = new ServerSocket(port);
    region socketHandler {
        mainLoop(serverSocket, socketHandler)
    }

def mainLoop(serverSocket: ServerSocket, reg: Region[r]) : Unit \ {Net, IO, r, Abort} = 
    let socket = serverSocket.accept();
    spawn handleSocket(socket) @ reg;
    mainLoop(serverSocket, reg)  

def handleSocket(socket: Socket): Unit \ {Net, IO, Abort} = 
    let reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
    let writer = new PrintWriter(socket.getOutputStream());

    processLine(reader, writer)

def processLine(reader: BufferedReader, writer: PrintWriter): Unit \ {Net, IO, Abort} = 
    match Object.toOption(reader.readLine()) {
        case Some(line) => {
            if (line.equals("bye")) {
                writer.write(line);
                processLine(reader, writer)
            } else {
                abort("see ya")
                
            }
        }
        case None => processLine(reader, writer)
    }