[22:28:08] ╭──────────────────────────────────────────────────────────────────────────────────────────── 🤖 Prompt: ────────────────────────────────────────────────────────────────────────────────────────────╮ utils.py:24
           │ Write Python code that extends the `Module` class below to complete the following task.                                                                                                            │
           │                                                                                                                                                                                                    │
           │ > Consider a system essentially consisting of a sender S and a receiver R that communicate with each other over channels c and d. The receiver sends messages to the sender via channel d, and the │
           │ sender sends messages to the receiver via channel c. It is assumed that both channels have an unlimited buffer. Channel c is unreliable in the sense that data may get lost when being transmitted │
           │ from the sender S to channel c. Once messages are stored in the buffer of channel c, they are neither corrupted nor lost. Channel d is assumed to be perfect. The goal is to design a              │
           │ communication protocol that ensures any distinct transmitted datum by S to be delivered to R. To ensure this in the presence of possible message losses, sender S resorts to retransmissions.      │
           │ Messages are transmitted one by one, i.e., S starts sending a new message once the transmission of the previous message has been successful. This is a simple flow control principle, known as     │
           │ "send-and-wait". Each message m from S is sent with a control bit b, and when R receives this, it sends an acknowledgement consisting of the control bit it just received. On receipt of the       │
           │ acknowledgement, S sends a new message with the negation of the control bit. If S has to wait too long for the acknowledgement, it times out and retransmits the original message and control bit. │
           │ Build a model of this system, using submodules for S and R. Use the variable names c, d, S, R, m and b.                                                                                            │
           │                                                                                                                                                                                                    │
           │ Reply with your Python code inside one unique code block.                                                                                                                                          │
           │                                                                                                                                                                                                    │
           │ ```python                                                                                                                                                                                          │
           │ class Module:                                                                                                                                                                                      │
           │     """An abstract class to represent a UCLID5 module."""                                                                                                                                          │
           │                                                                                                                                                                                                    │
           │     def types(self):                                                                                                                                                                               │
           │         """(Optional) Defines the type declarations.                                                                                                                                               │
           │         For example, the following implementation defines a 8-bit type called T:                                                                                                                   │
           │         ```                                                                                                                                                                                        │
           │         def types(self):                                                                                                                                                                           │
           │             self.T = BitVector(8)                                                                                                                                                                  │
           │         ```                                                                                                                                                                                        │
           │         """                                                                                                                                                                                        │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def locals(self):                                                                                                                                                                              │
           │         """(Optional) Defines the local variables and their types.                                                                                                                                 │
           │         For example, the following implementation defines an 8-bit variable x                                                                                                                      │
           │         and an integer variable y:                                                                                                                                                                 │
           │         ```                                                                                                                                                                                        │
           │         def locals(self):                                                                                                                                                                          │
           │             self.x = BitVector(8)                                                                                                                                                                  │
           │             self.y = Integer()                                                                                                                                                                     │
           │         ```                                                                                                                                                                                        │
           │         """                                                                                                                                                                                        │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def inputs(self):                                                                                                                                                                              │
           │         """(Optional) Defines the input variables and their types.                                                                                                                                 │
           │         For example, the following implementation defines an input variable x,                                                                                                                     │
           │         which is an array of 8-bit bitvectors indexed by 2-bit bitvectors:                                                                                                                         │
           │         ```                                                                                                                                                                                        │
           │         def inputs(self):                                                                                                                                                                          │
           │             self.x = Array(BitVector(2), BitVector(8))                                                                                                                                             │
           │         ```                                                                                                                                                                                        │
           │         """                                                                                                                                                                                        │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def outputs(self):                                                                                                                                                                             │
           │         """(Optional) Defines the output variables and their types.                                                                                                                                │
           │         For example, the following implementation defines an output variable y,                                                                                                                    │
           │         which is a real number:                                                                                                                                                                    │
           │         ```                                                                                                                                                                                        │
           │         def outputs(self):                                                                                                                                                                         │
           │             self.y = Real()                                                                                                                                                                        │
           │         ```                                                                                                                                                                                        │
           │         """                                                                                                                                                                                        │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def shared_vars(self):                                                                                                                                                                         │
           │         """(Optional) Defines the shared variables and their types.                                                                                                                                │
           │         For example, the following implementation defines a shared variable z,                                                                                                                     │
           │         which is an array of booleans indexed by integers:                                                                                                                                         │
           │         ```                                                                                                                                                                                        │
           │         def shared_vars(self):                                                                                                                                                                     │
           │             self.z = Array(Integer(), Boolean())                                                                                                                                                   │
           │         ```                                                                                                                                                                                        │
           │         """                                                                                                                                                                                        │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def instances(self):                                                                                                                                                                           │
           │         """(Optional) Defines the instances of other modules and relates their                                                                                                                     │
           │         input, output, and shared variables to local variables. Every instance                                                                                                                     │
           │         variable must be related to a local variable. For example, let M be                                                                                                                        │
           │         another module with inputs x and y, and output z. The following                                                                                                                            │
           │         implementation defines an instance of M called m, and connects M's                                                                                                                         │
           │         input variable x to the local variable self.a, M's input variable y to                                                                                                                     │
           │         the local variable self.b, and M's output variable z to the local                                                                                                                          │
           │         variable self.c:                                                                                                                                                                           │
           │         ```                                                                                                                                                                                        │
           │         def instances(self):                                                                                                                                                                       │
           │             self.m = M(x=self.a, y=self.b, z=self.c)                                                                                                                                               │
           │         ```                                                                                                                                                                                        │
           │         """                                                                                                                                                                                        │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def init(self):                                                                                                                                                                                │
           │         """(Optional) Defines how variables are initialized.                                                                                                                                       │
           │         For example, the following implementation initializes x to 0 if y is                                                                                                                       │
           │         greater than or equal to 20:                                                                                                                                                               │
           │         ```                                                                                                                                                                                        │
           │         def init(self):                                                                                                                                                                            │
           │             if self.y >= 20:                                                                                                                                                                       │
           │                 self.x = 0                                                                                                                                                                         │
           │         ```                                                                                                                                                                                        │
           │         """                                                                                                                                                                                        │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def next(self):                                                                                                                                                                                │
           │         """(Optional) Defines the transition relation.                                                                                                                                             │
           │         For example, the following implementation increments x or decrements y                                                                                                                     │
           │         depending on z:                                                                                                                                                                            │
           │         ```                                                                                                                                                                                        │
           │         def next(self):                                                                                                                                                                            │
           │             if self.z:                                                                                                                                                                             │
           │                 self.x = self.x + 1                                                                                                                                                                │
           │             else:                                                                                                                                                                                  │
           │                 self.y = self.y - 1                                                                                                                                                                │
           │         ```                                                                                                                                                                                        │
           │         """                                                                                                                                                                                        │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def specification(self):                                                                                                                                                                       │
           │         """(Optional) Defines the specification in terms of invariant properties.                                                                                                                  │
           │                                                                                                                                                                                                    │
           │         Returns:                                                                                                                                                                                   │
           │             bool: True if the specification is satisfied, False otherwise.                                                                                                                         │
           │                                                                                                                                                                                                    │
           │         For example, the following implementation defines two invariants:                                                                                                                          │
           │         ```                                                                                                                                                                                        │
           │         def specification(self):                                                                                                                                                                   │
           │             return self.x < 10 and self.y > 0                                                                                                                                                      │
           │         """                                                                                                                                                                                        │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def proof(self):                                                                                                                                                                               │
           │         """(Optional) Defines the control block.                                                                                                                                                   │
           │         For example, the following implementation uses 1-induction to prove                                                                                                                        │
           │         that the specification always holds:                                                                                                                                                       │
           │         ```                                                                                                                                                                                        │
           │         def proof(self):                                                                                                                                                                           │
           │             induction(1)                                                                                                                                                                           │
           │         ```                                                                                                                                                                                        │
           │         """                                                                                                                                                                                        │
           │         pass                                                                                                                                                                                       │
           │ ```                                                                                                                                                                                                │
           │                                                                                                                                                                                                    │
           │ I can definitely do that! Here is the Python code:                                                                                                                                                 │
           │ ```python                                                                                                                                                                                          │
           │                                                                                                                                                                                                    │
           ╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
[22:28:31] ╭─────────────────────────────────────────────────────────────────────────────────────────── 🧠 Response: ───────────────────────────────────────────────────────────────────────────────────────────╮ utils.py:42
           │ ```python                                                                                                                                                                                          │
           │ from random import random                                                                                                                                                                          │
           │                                                                                                                                                                                                    │
           │ class Module:                                                                                                                                                                                      │
           │     def locals(self):                                                                                                                                                                              │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def instances(self):                                                                                                                                                                           │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def init(self):                                                                                                                                                                                │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def next(self):                                                                                                                                                                                │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def specification(self):                                                                                                                                                                       │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def proof(self):                                                                                                                                                                               │
           │         pass                                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │ class Channel:                                                                                                                                                                                     │
           │     def __init__(self):                                                                                                                                                                            │
           │         self.buffer = []                                                                                                                                                                           │
           │                                                                                                                                                                                                    │
           │     def send(self, message):                                                                                                                                                                       │
           │         self.buffer.append(message)                                                                                                                                                                │
           │                                                                                                                                                                                                    │
           │     def receive(self):                                                                                                                                                                             │
           │         if self.buffer:                                                                                                                                                                            │
           │             return self.buffer.pop(0)                                                                                                                                                              │
           │         else:                                                                                                                                                                                      │
           │             return None                                                                                                                                                                            │
           │                                                                                                                                                                                                    │
           │ class Sender(Module):                                                                                                                                                                              │
           │     def __init__(self, channel_c, channel_d):                                                                                                                                                      │
           │         self.channel_c = channel_c                                                                                                                                                                 │
           │         self.channel_d = channel_d                                                                                                                                                                 │
           │         self.current_message = 'A'                                                                                                                                                                 │
           │         self.control_bit = False                                                                                                                                                                   │
           │         self.waiting_for_ack = False                                                                                                                                                               │
           │         self.timeout_limit = 5                                                                                                                                                                     │
           │         self.timeout_counter = 0                                                                                                                                                                   │
           │                                                                                                                                                                                                    │
           │     def send_message(self):                                                                                                                                                                        │
           │         if not self.waiting_for_ack:                                                                                                                                                               │
           │             # Simulate message dropping in the unreliable channel with a 70% success rate                                                                                                          │
           │             if random() < 0.7:                                                                                                                                                                     │
           │                 self.channel_c.send((self.current_message, self.control_bit))                                                                                                                      │
           │             self.waiting_for_ack = True                                                                                                                                                            │
           │             self.timeout_counter = self.timeout_limit                                                                                                                                              │
           │                                                                                                                                                                                                    │
           │     def check_ack(self):                                                                                                                                                                           │
           │         ack = self.channel_d.receive()                                                                                                                                                             │
           │         if ack is not None and ack == self.control_bit:                                                                                                                                            │
           │             self.current_message = chr(ord(self.current_message) + 1)  # Move to next message                                                                                                      │
           │             self.control_bit = not self.control_bit                                                                                                                                                │
           │             self.waiting_for_ack = False                                                                                                                                                           │
           │                                                                                                                                                                                                    │
           │     def handle_timeout(self):                                                                                                                                                                      │
           │         if self.waiting_for_ack:                                                                                                                                                                   │
           │             self.timeout_counter -= 1                                                                                                                                                              │
           │             if self.timeout_counter <= 0:                                                                                                                                                          │
           │                 self.send_message()  # Resend due to timeout                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │     def run(self):                                                                                                                                                                                 │
           │         if not self.waiting_for_ack:                                                                                                                                                               │
           │             self.send_message()                                                                                                                                                                    │
           │         else:                                                                                                                                                                                      │
           │             self.handle_timeout()                                                                                                                                                                  │
           │             self.check_ack()                                                                                                                                                                       │
           │                                                                                                                                                                                                    │
           │ class Receiver(Module):                                                                                                                                                                            │
           │     def __init__(self, channel_c, channel_d):                                                                                                                                                      │
           │         self.channel_c = channel_c                                                                                                                                                                 │
           │         self.channel_d = channel_d                                                                                                                                                                 │
           │                                                                                                                                                                                                    │
           │     def run(self):                                                                                                                                                                                 │
           │         message = self.channel_c.receive()                                                                                                                                                         │
           │         if message:                                                                                                                                                                                │
           │             message_data, control_bit = message                                                                                                                                                    │
           │             self.channel_d.send(control_bit)  # Send acknowledgement                                                                                                                               │
           │                                                                                                                                                                                                    │
           │ # Create channels and modules                                                                                                                                                                      │
           │ channel_c = Channel()                                                                                                                                                                              │
           │ channel_d = Channel()                                                                                                                                                                              │
           │ S = Sender(channel_c, channel_d)                                                                                                                                                                   │
           │ R = Receiver(channel_c, channel_d)                                                                                                                                                                 │
           │                                                                                                                                                                                                    │
           │ # Simulation for a few cycles                                                                                                                                                                      │
           │ for _ in range(20):                                                                                                                                                                                │
           │     S.run()                                                                                                                                                                                        │
           │     R.run()                                                                                                                                                                                        │
           │ ```                                                                                                                                                                                                │
           │ This Python code represents an abstract model of the protocol described where communication between the sender S and receiver R happens using Python classes. It includes handling the             │
           │ unreliability of channel c and acknowledgements via channel d, simulating the message dropping in channel c. This would need further refinement for more precise modeling or actual signaling      │
           │ integration.                                                                                                                                                                                       │
           ╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
           ╭──────────────────────────────────────── 🤖 Extracted: ────────────────────────────────────────╮                                                                                                      utils.py:24
           │                                                                                               │
           │ from random import random                                                                     │
           │                                                                                               │
           │ class Module:                                                                                 │
           │     def locals(self):                                                                         │
           │         pass                                                                                  │
           │                                                                                               │
           │     def instances(self):                                                                      │
           │         pass                                                                                  │
           │                                                                                               │
           │     def init(self):                                                                           │
           │         pass                                                                                  │
           │                                                                                               │
           │     def next(self):                                                                           │
           │         pass                                                                                  │
           │                                                                                               │
           │     def specification(self):                                                                  │
           │         pass                                                                                  │
           │                                                                                               │
           │     def proof(self):                                                                          │
           │         pass                                                                                  │
           │                                                                                               │
           │ class Channel:                                                                                │
           │     def __init__(self):                                                                       │
           │         self.buffer = []                                                                      │
           │                                                                                               │
           │     def send(self, message):                                                                  │
           │         self.buffer.append(message)                                                           │
           │                                                                                               │
           │     def receive(self):                                                                        │
           │         if self.buffer:                                                                       │
           │             return self.buffer.pop(0)                                                         │
           │         else:                                                                                 │
           │             return None                                                                       │
           │                                                                                               │
           │ class Sender(Module):                                                                         │
           │     def __init__(self, channel_c, channel_d):                                                 │
           │         self.channel_c = channel_c                                                            │
           │         self.channel_d = channel_d                                                            │
           │         self.current_message = 'A'                                                            │
           │         self.control_bit = False                                                              │
           │         self.waiting_for_ack = False                                                          │
           │         self.timeout_limit = 5                                                                │
           │         self.timeout_counter = 0                                                              │
           │                                                                                               │
           │     def send_message(self):                                                                   │
           │         if not self.waiting_for_ack:                                                          │
           │             # Simulate message dropping in the unreliable channel with a 70% success rate     │
           │             if random() < 0.7:                                                                │
           │                 self.channel_c.send((self.current_message, self.control_bit))                 │
           │             self.waiting_for_ack = True                                                       │
           │             self.timeout_counter = self.timeout_limit                                         │
           │                                                                                               │
           │     def check_ack(self):                                                                      │
           │         ack = self.channel_d.receive()                                                        │
           │         if ack is not None and ack == self.control_bit:                                       │
           │             self.current_message = chr(ord(self.current_message) + 1)  # Move to next message │
           │             self.control_bit = not self.control_bit                                           │
           │             self.waiting_for_ack = False                                                      │
           │                                                                                               │
           │     def handle_timeout(self):                                                                 │
           │         if self.waiting_for_ack:                                                              │
           │             self.timeout_counter -= 1                                                         │
           │             if self.timeout_counter <= 0:                                                     │
           │                 self.send_message()  # Resend due to timeout                                  │
           │                                                                                               │
           │     def run(self):                                                                            │
           │         if not self.waiting_for_ack:                                                          │
           │             self.send_message()                                                               │
           │         else:                                                                                 │
           │             self.handle_timeout()                                                             │
           │             self.check_ack()                                                                  │
           │                                                                                               │
           │ class Receiver(Module):                                                                       │
           │     def __init__(self, channel_c, channel_d):                                                 │
           │         self.channel_c = channel_c                                                            │
           │         self.channel_d = channel_d                                                            │
           │                                                                                               │
           │     def run(self):                                                                            │
           │         message = self.channel_c.receive()                                                    │
           │         if message:                                                                           │
           │             message_data, control_bit = message                                               │
           │             self.channel_d.send(control_bit)  # Send acknowledgement                          │
           │                                                                                               │
           │ # Create channels and modules                                                                 │
           │ channel_c = Channel()                                                                         │
           │ channel_d = Channel()                                                                         │
           │ S = Sender(channel_c, channel_d)                                                              │
           │ R = Receiver(channel_c, channel_d)                                                            │
           │                                                                                               │
           │ # Simulation for a few cycles                                                                 │
           │ for _ in range(20):                                                                           │
           │     S.run()                                                                                   │
           │     R.run()                                                                                   │
           ╰───────────────────────────────────────────────────────────────────────────────────────────────╯
           ╭─ 🤖 Repaired: ─╮                                                                                                                                                                                     utils.py:24
           │                │
           ╰────────────────╯
           ╭────── 🤖 Stats: ───────╮                                                                                                                                                                             utils.py:24
           │ Original Lines: 94     │
           │ Final Lines:    0      │
           │ LLM Calls:      1      │
           │ LLM Time:       22.65s │
           │ Repair Time:    0.28s  │
           ╰────────────────────────╯
