F10.9 Project: reliable delivery

Split message into packets of 14 characters, in the form <number>/<total>:<piece>. Deliver them to the Base with stop-and-wait. Print sent <number> each time you send a packet (including when you send it again) and print each reply you get. Never send the next packet before the last one is acknowledged. When every packet is acknowledged, print delivered in <n> transmissions, and turn the LED green.

# the two lines every program starts with: the commands, then the robot
from bugbot import *
connect()

message = "robot 7 reporting: mat clear, battery ok"

The hint students can ask for: For each packet, keep sending it until the reply is the acknowledgement for that packet's number. Count every send, including the repeats, and only move to the next packet once this one is acknowledged.

A solution

from bugbot import *
connect()
message = "robot 7 reporting: mat clear, battery ok"

def wait_reply(seconds=1.0):
    for tick in range(int(seconds * 10)):
        wait(0.1)
        for sender, text in messages():
            return text
    return None

pieces = [message[i:i + 14] for i in range(0, len(message), 14)]
packets = [f"{n + 1}/{len(pieces)}:{piece}" for n, piece in enumerate(pieces)]
count = 0
for n, packet in enumerate(packets, start=1):
    acked = False
    while not acked:
        send(packet)
        count = count + 1
        print("sent", n)
        reply = wait_reply()
        if reply is not None:
            print(reply)
        acked = reply == "ack " + str(n)
print("delivered in", count, "transmissions")
led(0, 255, 0)

Any program that meets the task's checks is marked correct in the simulator; this is one way, not the only way.