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Re: Interactive interpreter hooks

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On 2013-06-03 08:55, Steven D'Aprano wrote:
> The sys module defines two hooks that are used in the interactive
> interpreter:
>
> * sys.displayhook(value) gets called with the result of evaluating the
> line when you press ENTER;
>
> * sys.excepthook(type, value, traceback) gets called with the details of
> the exception when your line raises an exception.
>
> Is there a way to hook into the interactive interpreter *before* it is
> evaluated? That is, if I type "len([])" at the prompt and hit ENTER, I
> want a hook that runs before len([]) is evaluated to 0, so that I get the
> string "len([])".

You will need to write your own REPL for this. Use the code.InteractiveConsole 
class:

   http://docs.python.org/2/library/code

I recommend source-diving to see what you need to override, but I suspect you 
can just wrap around the `runsource()` method.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco

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Interactive interpreter hooks Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-03 07:55 +0000
  Re: Interactive interpreter hooks Fábio Santos <fabiosantosart@gmail.com> - 2013-06-03 10:00 +0100
  Re: Interactive interpreter hooks Terry Jan Reedy <tjreedy@udel.edu> - 2013-06-03 09:03 -0400
  Re: Interactive interpreter hooks Robert Kern <robert.kern@gmail.com> - 2013-06-03 14:19 +0100

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