How does one raise an EOFError using ‘Ctrl+D’ or similar from the keyboard in Pythonista?

[Tasilee]

I am doing a Harvard course on Python and they are using “except EOFError:” to terminate a program using a Ctrl+D.

Ctrl+D works fine on python on my PC and in visual studio browser environment (used by the Harvard course) but it doesn’t work in any combination that I can figure in Pythonista. I can see that the EOFError exception is supported.

Any ideas?

[cvpe]

Hi, I've asked your question to ChatGPT and after a lot of tries concerning stdin (=console) in Pythonista, it gave this code which is working.

import sys
from io import StringIO

# Simulate an empty input source
sys.stdin = StringIO('')

try:
    # Reading from empty stdin will raise EOFError immediately
    val = input("Simulating empty stdin: ")
except EOFError:
    print("EOFError caught with empty stdin.")

[qqfunc]

I think KeyboardInterrupt is a common way to terminate a program.

try:
    name = input("Enter your name: ")
except KeyboardInterrupt:
    print("Interrupted")

Press Ctrl+C to raise KeyboardInterrupt. In my environment, it was available for use in Pythonista.

[Tasilee]

@cvpe : I can't get that working in Pythonista, at least using some variant keyboard entry
@qqfunc: That indeed works, but it has raised what I believe is another issue with sys.exit(): The message in sys.exit is never displayed. Odd as this is kosher as far as I can see.

import sys
while True:
    try:
        val = input("Input: ")

    except EOFError:
        print("Printing: EOFError triggered"
        sys.exit("Exiting: EOFError triggered")

    except KeyboardInterrupt:
        print("Printing: KeyboardInterrupt triggered")
        sys.exit("Exiting: KeyboardInterrupt triggered")

    print (val)

[qqfunc]

Please note that the following is based on my knowledge of iOS and Python, but I don't know the exact mechanics of Pythonista.

First of all, Apple imposes many restrictions on iOS apps. For example:

• iOS apps cannot start other processes.
• iOS apps cannot use standard input / output to the same level as PC environments.

Pythonista does not start new process when running Python scripts, so exit(), quit(), and sys.exit() in Pythonista are different from their PC counterparts.

In case of sys.exit(), Pythonista seems to raise KeyboardInterrupt instead of terminating the Python process.

In conclusion, the concept of "exiting process" is no use in Pythonista. If you want a more PC-like environment, you might need an app that emulates a lower-level environment than Pythonista, such as a-Shell (although I haven't tested it with a-Shell).

[cvpe]

@Tasilee My (ChatGPT 🙄) code does not use any keyboard, it is only to show how an EOFError can be raised, by an empty stdin, thus EOF when you try to read it.
That doesn't help you, it was only for info.

to exit/stop a Pythonista script, I personally use os.abort()