Baffled by readline module

[Grant Edwards]

On 2023-03-10, 2QdxY4RzWzUUiLuE at potatochowder.com <2QdxY4RzWzUUiLuE at potatochowder.com> wrote:
> On 2023-03-10 at 12:57:48 +1100,
> Chris Angelico <rosuav at gmail.com> wrote:
>
>> On Fri, 10 Mar 2023 at 12:56, Greg Ewing via Python-list
>> <python-list at python.org> wrote:
>> >
>> > On 10/03/23 1:46 pm, Grant Edwards wrote:
>> > > That's not how it acts for me. I have to "import readline" to get
>> > > command line recall and editing.
>> >
>> > Maybe this has changed? Or is platform dependent?
>> >
>> > With Python 3.8 on MacOSX I can use up arrow with input()
>> > to recall stuff I've typed before, without having to
>> > import anything.

If you run this application from the command line, you get command
recall and editing when entering strings at the "cmd:" prompt?

#!/usr/bin/python
while True:
    try:
        line = input('cmd: ')
    except EOFError:
        print()
        break
    print('You entered "%s"' % line)

>> import sys; "readline" in sys.modules
>> 
>> Is it? Might be that something's pre-importing it.
>
> My ~/.pythonrc contains the following:
>
>     import readline
>     import rlcompleter
>     readline.parse_and_bind( 'tab: complete' )
>
> IIRC, that's been there "forever," certainly back into Python2, and
> probably back into Python1.  On my Arch Linux system Python 3.10.9, I
> get readline behavior with or without those lines.

I "get readline behavior" in the REPL without an "import readline",
but that's irrelevent.  We're talking about a command-line
application that's calling input().