err in the input builtin (original) (raw)

Created on 2017-09-27 06:34 by wt, last changed 2022-04-11 14:58 by admin.

Messages (9)

Author: Wren Turkal (wt)

Date: 2017-09-27 06:34

I would really love to add a few params to input so that it's signature looked more like so:

def input(prompt, /, *, fin=sys.stdin, fout=sys.stdout, ferr=sys.stderr): ...

This would certainly make overriding the the files in specific calls to input easier. A reasonable use case is collecting a piece over /dev/tty explicitly so that a redirected stdin could be used to pipe data into a program while overriding using /dev/tty to collect some piece of data. Here's some code illustrating what I'd like:

import sys sys.stdin.close() sys.stdin = open('/dev/null', 'r') with open('/dev/tty', 'r') as f: x = input('Name? ', fin=f) print(x)

FWIW, I have actually already implemented this fully (including tests). I am just trying to see what I need to do to allow release since I am work on my employer's time.

In the interest of getting feedback, does the signature provided above look sane?

msg303105 - (view)

Author: Wren Turkal (wt)

Date: 2017-09-27 06:41

This might also allow simplification of the getpass.unix_getpass() logic. I am not 100% sure about that yet though.

msg303132 - (view)

Author: R. David Murray (r.david.murray) * (Python committer)

Date: 2017-09-27 12:52

This is probably a topic for the python-ideas mailing list. For example, rather than complicating input, it might be better to propose adding a redirect_stdin to contextlib to parallel the two existing redirect context managers. I don't remember why that was not added when the others were, but there was probably a reason, so a discussion about what the best solution is for the use case is in order, and python-ideas is the place for that.

msg303135 - (view)

Author: Serhiy Storchaka (serhiy.storchaka) * (Python committer)

Date: 2017-09-27 13:06

input() is a convenient function for simple user interaction. If you need to read a data from different file object just use its readline() method.

msg303297 - (view)

Author: Wren Turkal (wt)

Date: 2017-09-29 05:31

Added a PR to facilitate discussion on python-ideas.

msg338208 - (view)

Author: Cheryl Sabella (cheryl.sabella) * (Python committer)

Date: 2019-03-18 12:04

For reference, here's the link to the Python ideas thread: