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To: python-list@python.org
From: Terry Reedy <tjreedy@udel.edu>
Subject: Re: buggy python interpretter or am I missing something here?
Date: Thu, 30 Jan 2014 04:44:39 -0500
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On 1/30/2014 12:13 AM, Gregory Ewing wrote:
> Steven D'Aprano wrote:
>> On Mon, 27 Jan 2014 12:22:22 -0800, Rick Johnson wrote:
>>
>>> Why do we even need an "input" function anyway if all it is going to do
>>> is read from stdin?
>>
>> That's not all it does.

What else it does is print a prompt before reading and to strip off the 
trailing newline.

>> For example, it handles backspacing, so that typing H E L O O
>> BACKSPACE BACKSPACE L O gives "HELLO" rather than "HELOO\x7f\x7fO".
>
> No, it doesn't -- that's handled at a lower level.
> Any other method of reading from stdin, as long
> as it hasn't been redirected away from the console,
> has the same behaviour.
>
> I typed some backspaces in the input to each of the
> following experiments, and they didn't end up in the
> data:
>
>  >>> import sys
>  >>> x = sys.stdin.readline()
> HELLO
>  >>> x
> 'HELLO\n'
>  >>> import os
>  >>> f = os.fdopen(0)
>  >>> y = f.readline()
> adsxx
>  >>> y
> 'adsxx\n'
>
> So input() really is a pure convenience function.
> (That doesn't mean it's not worth having, though!)

It is equivalent to

def input(prompt):
   sys.stdout.write(prompt)
   return sys.stdin.read(<one line>)[:-1]

There was once an eval around the return, but that was determined to be 
a bad idea.

-- 
Terry Jan Reedy