input vs. readline

[Terry Reedy]

On 7/8/2016 7:17 PM, John Nagle wrote:
>    If "readline" is imported, "input" gets "readline" capabilities.
> It also loses the ability to import control characters.  It doesn't
> matter where "readline" is imported; an import in some library
> module can trigger this.  You can try this with a simple test
> case:
>
>    print(repr(input()))
>
> as a .py file, run in a console.  Try typing "aaaESCbbb".
> On Windows 7, output is "bbb".

The escape key erasing input back to the beginning of the line is 
Command Prompt or cmd.exe behavior.  Type anything at a normal
command prompt and hit ESC.  Input one.  It has nothing to do with 
Python or the readline module.

> On Linux, it's "aaa\x1bbbb".

The interpretation of control characters is terminal-specific.  IDLE's 
shell uses the same editing keys
as the editor window, which depend on OS and user customization.
Note that Python statement input is multiline, not single line.
It does not try to imitate any particular terminal and does not
normally recognize ESC.

>    What's the best way to get input from the console (not any
> enclosing shell script) that's cross-platform, cross-version
> (Python 2.7, 3.x), and doesn't do "readline" processing?

Run Python in a cross-platform, cross-verson shell.  IDLE with a fixed 
key set would qualifiy except a) inputting literal control chars would 
not work, and b) normal key sets do not work on both Mac and other systems.

I don't know how close other IDEs come.

-- 
Terry Jan Reedy